ToME: the Tales of Maj'Eyal

I'm toying around with adventurer builds, and I'm curious how arcane combat(gives a chance to trigger a spell on a melee attack) and corrupted strength(gives a free melee attack on casting a spell) interact? Does it create an endless loop or do they not work together at all?

Corrupted Strength will proc, but it only works once per action. So it's a synergy but not a feedback loop.

From what I heard, it used to be a feedback loop. It may have been changed though.

corrupted strength triggers a free atack, on a spelcast THAT TAKES A TURN.
arcane might trigger a free spell cast on successful melee attack.

if you cast a fireflash, you will trigger corrupted strength that i think can trigger a spell.
but there it stops. because the procks don't take a turn, it does not trigger another corrupted strength.
also, if you cast the flame to trigger strength, flame goes on cool down, which means you have to have another spell off cool down to be triggered. and there are currently 3 spells (including the flame) that can be cast by arcane might.

Note: if I remember correctly it didn't use to be 1 per turn so you could go into a loop (very old versions).

This is correct. And AC still works this way, and can proc multiple times. Corrupted strength was changed to only proc once per turn, which nerfed it with other things as well. (Previously, you could cast a spell that hit two enemies in melee range, like bone nova, and corrupted strength would proc on both, and I feel the absence of that is a significant downside.)

Because arcane combat can trip more then once, you can also use 'flurry (melee attack) -> Various arcane combat triggers (magic attack) -> Corrupted strength (Physical attack) -> Arcane Combat Triggers (magical attack) -> Ends, because corrupted strength no longer procs more then once a turn.

Mind you, I'm not certain of the exact mechanics of the interaction between multi-hit attacks that trip arcane combat and corrupted strength, if it will interrupt and drop it's damage in the middle, or at the end, or what. But you can start with a melee attack or talent, which triggers the arcane combt spell, which will trigger corrupted strength, which has a chance to trigger the arcane combat spell again. So for optimal builds using this combo, you should not 'start' with a spell.

It doesn't really mater, at the end of it's just an extra attack, back when (if) there was the possibility of infinite spam with it, it wouldn't either.

Also the corrupted strength goes AFTER the spell is sent out last time I checked.