Brann is an NPC that helps you in Delves. Brann cannot be leveled unless the Delve is bountiful. I've noticed that there's little to no leveling effect to Brann unless it is a Delve Tier 5 or above it seems. This is a Tier 7.
In this video I missed a chest and had to go back after the end to get the chest. Advise: Stand on top the cart under the chest and jump and then right click when the loot cursor is active. The XP loot on the scaffolding can be easy if you stand as close as you can to it on the platform.
@cogantarighy7823