If you wish to raise a creature's power so its mentor ability can target a bigger creature, the last chance you have to do so is during the beginning of combat step
But unless youre going to be using him to knock down locations, I dont see much of a use for this particular card
You need to convince your opponents that yes, you actually do need that Bolas's Citadel to save them and yes, you do need the Damnation in your graveyard to wipe the board
While its retrain, the Initiative, did extremely well, original Dungeons have largely gone unexplored in most formats
ISBN 978-1-78618-067-4
The rulings for the Mystery Booster set state that a supplementary token card (physical object) with a Magic card back must be used to represent token cards (game object) in hidden zones like the library or hand, but also point out no such cards exist, "so you may need to be creative." Players at events using test cards might represent them with typical token marker cards meant for regular tokens, or write over basic lands or other expendable cards