[@HarbingerKurahi]
To break it down dude.

Your character isn't ultra high by any definition, he's just got an ultra high tier power. 

The poison immunity doesn't matter TBH, I'd say there's like four total poison users active at  any point in time. Myself included.

Storm Caller's heat generation is pathetic and outstripped by an intermediate tier character.

Here's a list of things it can melt.

Copper, Antimony, Aluminum, (low quality) brass, cadmium, bismuth, lead, magnesium, silver, sodium, zinc. (This is not a complete list, but anything usable in a weapon is not listed here.)
Every single one of those can't be weaponized, save for silver, but that's because of its magical effect against Werewolves (And sometimes vampires and undead in general.)

About his first sword. Excusing the fact that mind control powers are a no-go, PERIOD. 

Nobody in ultra-high tier can be considered weak willed.

In fact I'd say just about no character in a combat setting can be considered weak willed. 

Even my bear character, who is BEARly capable of conscious thought, has a strong will. Demonstrated in [@Skallagrim]'s Multiverse, where he had just been killed by a demon and requested to be sent to fight an even stronger malevolent entity. Despite knowing that he wouldn't survive.

Unbreakable weapons are a mainstay so really no complaint here.

The black lightning is the only power that has any semblance of high to ultra high tier, but the kicker is. Any ultra high tier character could survive it and move in to absolutely obliterate your character. Because if the black lightning doesn't instantly kill them,  Harbringer here is absolutely outclassed in every regard.

HELL, simply by EXISTING near four of my five Ultra-high tier characters he'd be obliterated.

Sterling's shredding wind barrier produces winds strong enough to tear steel like paper.
Kynion's entropy aura can only be resisted by another entity with an equally strong aura.
Shael's dark energy aura blasts matter apart near his body and follows the above rule.
Wanderer's body generates heats up to 14,500k. Anything that's not higher tier near it dies.

And these are just the passive abilities of Ultra-High tier characters.

There's a reason why they are literally never used, it's because for writing purposes they are background characters.

The black lightning, at the tiers he fits into, is unfair to anyone else in those tiers. (Intermediate as he is and High if you buff his physical ability.)

And in the tier you believe he's in, he's so underwhelming that he'd die nearly instantly.

This is the point I'm trying to get across.

This is why absolutes don't work.