25 con + Tattoo of the lost incarnation = holy crap.

[Yes, I have a Mic.]

You regenerate 2 hp roughly every half second as far as I can tell. Its enough to basically shrug off blows from all comers.

"25 con? I haven't got time for that pal. I got to max wisdom, intelligence and charisma."
Fair point. Well you can get two items that increase the constitution of lawful good characters by 1 and two rings called "Aegis of Torment" that both increase con by 3 but they're only available near the end of the game.
This means you can get away with 17 constitution but makes it an end game strategy.
Still, pretty cool .

[Captain Pentium]

Extremes with the stats in this game are almost always rewarding. High social skills and intellect? Talk yourself out of anything.
High strength and constitution? Become an unkillable god that can bash a Deva’s face in with ease.

[St. Haborym]

From what I remember of this game, having that tattoo equipped with maxed con doesn't actually help, because you regen +1hp twice, whereas without it equipped you regen +2hp once, meaning it's exactly the same either way. Unless that was a bug in the original game that got fixed in the EE?