Best tank to pair with monk?

[Shurrikhan]

The war debuff does both physical and magical damage so it's better than either, plus the magic damage reduction stacks with the int down. That being said, you can really stick with whatever tank you like best. The world first clear on the current savage content was done with a drk and mnk in party. The Int down debuff is becoming less and less relevant anyways thanks to darkness type damage.

Darkness type? I would think that a Int debuff would reduce all outgoing spell damage, even if "true damage", as it affects the source stat rather than interacting with the damage type itself. Which is probably why almost every "true damage" (non-mitigatable) attack I can think of has been while the attacker/source isn't targetable (e.g. "Ragnorok" casting the spells in T9, rather than Nael). If that's a non-mitigatable type I could however see Storm's Path becoming useless against it.

[Kitfox]

Darkness type? I would think that a Int debuff would reduce all outgoing spell damage, even if "true damage", as it affects the source stat rather than interacting with the damage type itself. Which is probably why almost every "true damage" (non-mitigatable) attack I can think of has been while the attacker/source isn't targetable (e.g. "Ragnorok" casting the spells in T9, rather than Nael). If that's a non-mitigatable type I could however see Storm's Path becoming useless against it.

The Darkness damage found in current Savage Midas is not spell damage, it doesn't count as physical or magical, it is a seperate type. That's why it's not affected by STR and INT debuffs. If there's a source stat, none of the player abilities reduce it. Only universal damage reductions and shields work: Storm's Path, Reprisal, Rampart, Vengeance, and so on. That being said, darkness type attacks are very few compared to all the physical and magical damage so INT and STR debuffs are still extremely valuable to have around.

On topic: MNK is best paired with PLD+WAR setup, in my opinion, for the variety of debuffs they provide. Out of those tanks, WAR is by far the more flexible one if you're likely to run a lot of 4-man dungeons, as PLD is by far the worst tank for those due to the lack of AoE damage. Honestly it doesn't matter much unless you're planning on raiding and want to optimize your party setup, DRK is still very viable in all content and just as good as WAR for dungeons.