As I remember seeing pointed out on /r/DestinyLore or /r/DTG, the lore entries make clear that the individual referred to in the Heart of Inmost Light lore tab is Rezyl Azzir–by using a key phrase “muscle and might and metal”, and both also referring to Azzir as a “mountain” of these attributes.
Seen first in a D1 lore card here:
In time his kind would be called Titan. Mountains of muscle and might and metal.
And then in the D2 exotic lore tab:
Muscle and might and metal—a mountain of it, they said.
I’m proposing adding the latter entry to the Rezyl Azzir category. I’d argue it could stand as a Level 3 since it refers directly to him and his inmost (heh) thoughts. But it doesn’t mention him by name and could be bumped down to Level 2. Thoughts?