Where:
The Tower: Near the Curcible Quartermaster

What:

Armor (Y2):
Twilight Garrison
Achlyophage Symbiote
The Stag

Weapon (Y2):
Super Good Advice

Legendary Engram (Y1):
Helmet

For added disappointment on boss kills and faction rank up packages.

Every time I rank up in Vanguard, I get super excited. Just this week, I walked up to Cayde and he was grinning ear-port to ear-port. His mouth was all lit up and everything. I asked him what he was so happy about, and he gave me this:

My first one, by the way. Every time I hit the Vanguard, I'm pretty much guaranteed to get something that's at least 5 light levels higher. And it's awesome!!!