Flashback, an old mechanic brought back to the game
Dealing combat damage with Elsha gives you that many 1/1 Monk tokens with prowess, so spells that let you slip past blockers and gives Elesha a power boost helps to make them an all-in strategy
With the premise that most decks running Outpost Siege will appreciate the card advantage half, the best decks for it will be the ones that can take advantage of the Dragons mode as well
The effect and the card itself is super sweet, and if someone would bring one to a casual game night or competitive Tribelander tournament I hosted, I would deem it legal to play
After that, I create a loose thumbnail sketch and if something needs to be further clarified, there will be a loose sketch for that as well
A venturing into the dungeon deck, with cards like Planar Ally and Nadaar, Selfless Paladin would be loads of fun