He DID NOT have any regen powers before he became a monster. His original powers was covering his skin with exoskeleton. That's it.
His current appearance where he looks like a skull monster and can regenerate himself is something he gained AFTER he turned into a monster when he was trapped inside the Gate.

He's the Medicine God, and they already met back in ch 64.
He's one of the old people gang who acknowledge him as "the world's strongest".
The girl wasn't there during their meetup tho, so she doesn't even know they're already acquainted.

Girl, you don't even know their relation. Put your rage boner down, this is a wendy's

His og ability was covering himself with exoskeleton. But the process is painful for him.
And when the exoskeleton disappears, it leaves disgusting scars on his skin, which everyone makes fun of him.

Every old man in this manga is ugly af

looks at Rachel from Tower of God:

Lakrak's a dad !!!

Dang... she's awesome

Wouldn't they join forces with her and cause mayhem together, or smth

But with 3 giant fish instead

And also giving them more excuses to keep on killing more innocents, coz they know they can just get away with it since he just sets them scot-free

?
What?
Is he a transcendent being too?

WHAT !!?

The mangaka just decided to change Ignia's design to the anime one, LOL
But why xDhttps://i.postimg.cc/K8q7nF6J/i.png https://i.postimg.cc/gjW3Y0hk/i.png

*Sore loser to the core

Aw man,, it's over... and he still didn't find a house.

Now he just throwing accusations around. Sore loser much.

The way this mangaka draws old men with those small-ass eyes bother me sooo much.
That bearded old man looked so off with those eyes.

Why is there a whole chapter around this B1tch, S K I P

Letty finally meets Varney
Varney reunites with Dearia

Definitely one of my favorite chapters yet, in this whole series

Translation choices probably led to that modernized metaphors.
I don't know if the original text also went with "docile as a dog", or if Korean has a similar metaphor, and the English translators went with that modern one when they translated that line.