Aghanim's Shard

"With origins known only to a single wizard, fragments of this impossible crystal are nearly as coveted as the renowned scepter itself.

While Aghanim's Shard is in your inventory, 2/round you can add 1 nen instance to a basic nen technique. If you use an advance ability that combine more than one basic technique, you can only add one nen instance.   

If Aghanim's Shard is attuned, you gain +1 nen instances to every nen technique that you know (they still have the same limitations). Additionally, you can activate Nen Overpower skill.

Nen Overpower: For 1d4 rounds, you can surpass the SIZE of nen dices that you possess in one level. Use bigger dices requires to expend aura as usual. This ability can't be used again until short rest. 

Aganim's Shard can be consumed. If you consume Aganim's shard, it loses the Nen Overpower activated ability, but does not requires an attuned slot.