9 min read


You might remember Equinox if… if you were reading Marvel Team-Up (or a reprint) during the 1970s. Which is fairly niche. Though he has since returned in newer stories.

Back during the seventies I thought that Equinox had a cool name and was impressive. But, in the words of Dr. Liara T’Soni, “I was… very young”.

Still, he’s an easy-to-use superhuman with dynamic powers and good visuals.



  • Real Name: Terrance Sorenson.
  • Other Aliases: The Thermodynamic Man. One caption erroneously calls him the “thermonuclear man”.
  • Known Relatives: David Sorenson (father, deceased), Dr. Margay Sorenson (mother), unidentified wife (deceased), Janet Sorenson (daughter).
  • Group Affiliation: Initiative, Freedom Force (Initiative version), Vil-Anon.
  • Base of Operations: New York City area.
  • Height: 6′ (1.82m). Weight: 200 lbs. (91 Kg.).
  • Eyes: Brown. Hair: Bald.

Powers & Abilities

Equinox can will his body to enter a state of thermodynamic flux. Parts of his body will absorb heat and catch fire like the Human Torch, and parts of his body will repulse heat and become ice-covered like Iceman.

This phenomenon moves down from his head to his feet, doing a full vertical sweep every 6-7 seconds.

The flaming parts can shoot flames and the icy parts can shoot cold. This too is comparable to the Human Torch (Johnny Storm) and the Iceman (Robert Drake). However, Equinox isn’t as accomplished with his powers as they are.

Other assets

In his superhuman state, Equinox has superhuman strength and durability.

Early on he seemed to be about “Class 2”. But more recent sourcebooks have him pegged at “Class 20”.

Likewise, in 1974 he could still be hurt by ordinary punches. But by 1977 he could take “Class 10” attacks and keep on truckin’.

His heat/cold aura could also stop bullets.

According to Equinox, this increase is because he was now accepting his powers rather than fighting them. Allegedly, every thermodynamic ripple cycle is making him stronger.

In his earliest appearances he wore a metallic, anonymising containment suit. Its non-slick surface defeated the webbing of Spider-Man (Peter Parker). Or at least the formula Parker was using back in 1974.

He’s also fast and agile. He could leap atop a moving car, then atop a nearby moving bus.

Equinox (Marvel Comics) (Spider-Man enemy)


Equinox was first glimpsed in 1974. But his appearance was an enigmatic one. He was clad from head to toes in a featureless costume, and stealing scientific research hardware.

Spider-Man (Peter Parker) once failed to stop him, as did the Torch (Johnny Storm).

Equinox’s use of ice powers led to Storm accusing the mutant Iceman (Robert Drake) of being the thief. But after this misunderstanding, the two lads ended up fighting Equinox. They discovered his powers after Mr. Storm damaged the containment suit.

Equinox vanished in an accidental explosion, and wasn’t seen again for a few years. Which is when we learned about his background.

The H-index always was a mistake

Terry Sorenson is the son of two scientists.

Dr. Margay Sorenson is the head of Natural Sciences at Bard  . She seems to be a biochemist.

Her husband David was a physicist.

However, unlike Margay’s, David Sorenson’s work was poorly received by his peers. He gradually sank into bitterness, alcoholism and domestic violence. Margay left as soon as Terrance was old enough.

Equinox (Marvel Comics) containment suit vs. Torch

With the containment suit on.

Thermal shock

One night, as Margay and 17-year-old Terrance came to visit, David’s makeshift lab accidentally caught fire.

Terrance went in to get David out of the blaze, but the equipment exploded. David was killed and Terrance was heavily mutated.

Margay worked for years to reconstruct David’s work and cure Terry. But none of the attempts worked.

Terrance started stealing valuables in Manhattan to fund this research, as Margay’s savings were running out. Which is what had led to the 1974 clash.

A Sorenson of fire and ice

By 1977, Terry Sorenson was losing it. He ambushed and nearly killed Spider-Man as revenge, then went on a rampage.

Spidey, plus Yellowjacket (Dr. Henry Pym) and the winsomeAttractive in a fresh and youthful way Wasp (Janet van Dyne) tried to stop him. But they were outgunned.

Ms. Sorenson tried to intervene, but Equinox’s power was now too strong for her power control beam.

As he clashed with a NYPD unit led by Jean DeWolff, Equinox accidentally destroyed electrical equipment. This plunged a large chunk of New York City into darkness.

Parker and Dr. Sorenson used Reed Richards’ lab (the FF were away) to build stronger depowering equipment. Equinox invaded the Baxter Building, but with van Dyne and Pym’s help he was neutralised.


Over decades, it was possible to treat Terrance Sorenson to bring his powers under control. He thus regained his rational mind.

He eventually married, and the couple had a daughter.

By 1994, Mr. Sorenson was in a bad situation. His wife had died some years before, and he couldn’t find a job.

Little Janet Sorenson was assigned a social worker, Sam Wilson. But Mr. Wilson came to suspect that Terry was beating Janet.


As the Falcon, Sam discovered the truth. Janet had inherited Equinox’s powers, but couldn’t control them. Terrance had no idea what to do. He was threatening his daughter to stop her from emitting uncontrolled bursts of fire.

As the Falcon and as Wilson, Sam obtained help for the both of them.

Mr. Sorenson was later seen in Villains Anonymous meetings. This is a support group for former costumed and/or superhuman criminals. Presumably, this was where Mr. Wilson directed him.

Equinox was also seen running power tests for Project: PEGASUS. Presumably, PEGASUS researchers were the ones whom the Falcon had contacted to help Janet.

Equinox (Marvel Comics) (Spider-Man enemy) with legs ablaze

The 2000s

In 2006, Equinox was trying to escape from the Superhuman Registration Act by getting a fake ID.

The quote Heroes endquote for Hire intervened, using textbook entrapment to execute on blatantly unconstitutional legislation.

Mr. Sorenson ended up imprisoned in the Negative Zone gulag, apparently for several years.


During the Initiative project, Equinox seemed to have joined the Montana response team, the Freedom Force (no — well, not much — relation).

He was under the command of the Challenger and working with Cloud 9, Think Tank and Spinner.

However, this Equinox was — during at least part of the Initiative project — a Skrull impostor.

Equinox (Marvel Comics) Margay Sorenson

Margay Sorenson.

Early 2010s

In 2012, Equinox was seen torching a building and attacking the NYPD to keep them at bay. He may have been hired for criminal arson.

Spider-Man (Peter Parker) stopped him cold (so to speak) using specially-designed weaponry.

Sorenson was transferred to the Raft, then to the Tabula Rasa prison.

However, a major riot soon took place there. Rogue (Anna-Marie NLN) responded. She asked prisoners to volunteer their powers to help her fight the mutineers.

Equinox immediately volunteered. He hoped to be rewarded with time served – and thus be reunited sooner with his daughter.

Late 2010s

In 2016, Equinox became a henchman for a chronal splinter of Kang the Conqueror – possibly against his will.

Kang multiplied him into an army by bringing back to the present versions of Equinox from the very near future.

However, Spider-Man (Miles Morales) of the Avengers deduced which version of Equinox was from the present. He knocked Sorenson out, making all future copies blink out of existence.



During his 1970s rampages, Equinox was drunk on power. He could feel enormous might swelling within him, and murderously exulted in his ability to destroy and vanquish.

When less excited Mr. Sorenson seemed to mean well – but to have serious trouble sticking to that agenda.

In 1977, Dr. Henry Pym noticed that Equinox kept alternating between an adult vocal tone and a teenage one. This likely hinted at Equinox combining the consciousnesses of David and Terrance in some fashion. There’s no further data.

Equinox (Marvel Comics) vs. Spider-Man classic shot

DC Heroes RPG

Equinox (1974)

Dex: 05 Str: 07 Bod: 05
Int: 04 Wil: 03 Min: 04
Inf: 05 Aur: 03 Spi: 04
Init: 014 HP: 020


Cold immunity: 06, Flame immunity: 06, Friction control: 05, Ice production: 08, Flame project: 08

Bonuses and Limitations:

  • Flame project has Autofire.
  • Friction control is limited to lowering friction, and to a 0 APs Area on an immobile, firm surface.
  • Ice production is limited to Physical attacks, though these can have the Blunt or the Cold Descriptor.


Acrobatics: 05


None demonstrated.


Margay Sorenson (High).


Minor Rage, Strange Appearance, Misc.: if hit by an energy attack that scores a double, Equinox uncontrollably releases Bomb: 09. This doesn’t attack him, but it consumes one Automatic Action. If he’s out of Actions for that Phase, the explosion takes place as his first Action during the next Phase after a short buildup.








CONTAINMENT SUIT [BODY 02, Grappling Immunity: 06]. The suit *might* dampens Equinox’s Powers, but if so it wasn’t observable.

Design notes

The 1974 stats are seen but briefly. So most is speculative.

But I figured they’d be useful if somebody somewhere needed stats for a less powerful Equinox. No need to thank me, just send cash and 12-gauge shotshells.

Equinox (Marvel Comics) with his daughter Janet no costume

Terrance and Janet (from a hispanophone edition).

Equinox (1977)

Dex: 06 Str: 10 Bod: 07
Int: 04 Wil: 03 Min: 04
Inf: 05 Aur: 04 Spi: 04
Init: 015 HP: 045


Cold immunity: 07, Flame being: 04, Force field: 02, Icing: 04, Flame immunity: 07, Friction control: 05, Ice production: 09, Flame project: 09, Skin armour: 02

Bonuses and Limitations:

  • Force field only vs. projectiles.
  • Friction control is limited to lowering friction, and to a 0 APs Area on an immobile, firm surface.
  • Neither Flame Being nor Icing come with an Attack Vulnerability, for simplicity’s sake. Like, the abstract noun, not the Japanese drink.


Acrobatics: 04


None demonstrated.


Margay Sorenson (High).


Minor Rage, Strange Appearance.







Later on

Once the treatments work, Sorenson acquires an Alter-Ego (human form) and Dependants (his family).

He can still turn into his Equinox form. But he doesn’t get his full power right away – it rises through heat/cold cycles and exertion.

There’s a remark in 2016 about Equinox being more powerful than he should have been. It wasn’t that apparent in the material, so I suspect that somebody was still making assessments based on 1974 data.

Equinox - Marvel Comics - thermodynamic cycle - art by ronniethunderbolts

Art by Ronniethunderbolts.

Writeups.org writer avatar Sébastien Andrivet

By Sébastien Andrivet.

Source of Character: Marvel Comics.

Helper(s): Darci. For the previous version Hart, Jackson, Peter Piispanen.

Writeup completed on the 28th of March, 2020.