PSA: Don't toss your old darklight gear

[Alkimi]

I'm sure we need to level up the retainer to 50 first before he can wear DL.

Yeah, from the video it seems like you have to use a new sort of currency (no idea what it is, some sort of silver coin) to pay your retainer to fetch items from either gathering or hunting mobs. He/She will then gain exp from that and gradually level up allowing you to gather/hunt higher level stuff.