Keeper of the Quiet Hour is a common Artifact Creature — Chimera card from Reality Fracture (FRA), collector number 171. Current market price: $0.11 (foil $0.25), TCGplayer market prices via Scryfall.
When this creature enters, empower Jace 2. (Put two loyalty counters on a Jace token you control. If you don't control one, first create a blue Jace planeswalker token with "[−1]: Surveil 1" and "[−3]: Draw a card.")