If I true polymorph myself, when I make a concentration save, should I use my character's or monster's statistics?
And if I have relevant feats can I use them?
If I true polymorph myself, when I make a concentration save, should I use my character's or monster's statistics?
And if I have relevant feats can I use them?
I think this should be pretty clear based on the wording of the spell:
If you turn a creature into another kind of creature, the new form can be any kind you choose whose challenge rating is equal to or less than the target's (or its level, if the target doesn't have a challenge rating). The target's game statistics, including mental ability scores, are replaced by the statistics of the new form. It retains its alignment and personality.
Emphasis mine. So, your Constitution score and any bonuses to Constitution saving throws would be those of the creature you transformed into.
As per this question, you wouldn't benefit from any feats or other class features unless the new form had those as well.
True Polymorph states that all statistics and ability scores are replaced by the statistics of the new form. There is the relevant part highlighted:
Creature into Creature. If you turn a creature into another kind of creature, the new form can be any kind you choose whose challenge rating is equal to or less than the target's (or its level, if the target doesn't have a challenge rating). The target's game statistics, including mental ability scores, are replaced by the statistics of the new form. It retains its alignment and personality.
So you use the Constitution saving throws from the creature instead of your PCs. Even Jeremy Crawford reiterated this in a Twitter post.
The same goes for feats.