Buddy System IX

I had Brann at 89 something. I went to level him up to 90 and the achievement didn't trigger. Must be current expansion companion only.

Tips on farming Brann XP:

While you do have to complete Bountiful Delves, you do NOT need a key. This means you can simply complete Bountiful Delves on alts. The XP is awarded on completion, not chest unlock.

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• This awards ~55k XP on T11 Bountiful
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Be sure to kill the 4 groups of Ethereal enemies throughout the delves to be awarded the Nemesis Strongbox at the end of the delve.

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• This awards ~24k XP on T11 Bountiful
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Since you are farming Bountiful Delves, there will always be a Flickergate. Try to find it, as it awards a Flickering Spoils at the end of the delve.

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• This awards ~30k XP on T11 Bountiful
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In total, if you do the above for each Bountiful Delve you should earn ~109k XP. This is around 0.5 levels per delve at the 90-100 range.

Happy farming!