The Three Houses Perfect Guide, a strategy guide for the newest Fire Emblem game published by Japanese gaming magazine Famitsu, is set to release tomorrow. A leaked page from this guide, revealing the game’s future DLC plans, was translated and shared by SerenesForest. According to the information in the guidebook, the Fire Emblem: Three Houses DLC schedule is as followed:

(Minor spoilers for Fire Emblem: Three Houses)

Wave 3, to be released by the end of 2019:
Free update:
-New playable character: Jeritza (only available on some routes)
-New support conversations (most likely featuring Jeritza)
-New unspecified activities and online features

Paid DLC:
-New playable character: Anna
-New unspecified monastery facilities
-Additional unspecified online features
-New paralogue with Anna and Jeritza
-New monastery activities: Sauna and Playing with Animals
-Maid and Butler DLC outfits and battalions

Wave 4, to be released by May 2020:
Paid DLC:
-Side story: Abyss Mode
-New playable characters: Juris, Balthazar, Constanze, and Javi (rough translations of their Japanese names; their release or English names may differ)
-New support conversations (most likely featuring the new playable characters)
-New unspecified monastery facilities
-4 new classes
-New enemy monsters
-New Hero’s Relics
-New paralogues
-New quests
-New battalions
-New gambits
-New unspecified costumes for Male Byleth, Female Byleth, and Sothis

Note that this is all currently unconfirmed information. The official announcements for at least Wave 3 of the DLC will most likely come later this year.