You know those collab events some Gacha Games have with like cafes and stuff where they draw their characters in pretty clothes or butler/maid outfits?
40k Phoenix Lords x some cafe collab event, that is either:
1) All Phoenix Lords wearing butler suits with their own aesthetic. Jain Zar and Lhykhis are also wearing a Howling Banshee and Warp Spider themed butler suits.
2) All Phoenix Lords are wearing their own themed maid dresses, not just Jain Zar and Lhykhis. Some Phoenix Lords are portrayed as very flustered or embarrassed, while others seem to be completely cool with it. Fuegan's maid dress has those cool flame design on the fabric. Maugan Ra's is skeleton themed. Baharroth's is paradise bird themed and has lots of feathers.
3) Male Phoenix Lords are wearing maid dresses, while Jain Zar and Lhykhis are wearing butler suits.