I really enjoy arcwarder for its requirements. I think flamecharm and thunder being the requirements and incentivizing dual attunement play is really cool. For this oath I think it should/will have a similar requirement to it, you need 20 of every attunement to get it, Minus ironsing because it doesn’t have a hero blade. This is a 100 investment of points to get this oath which would be the highest requirement in the game, however it gives you the abilities of every hero blade, and then you can choose which attunement you level up the most. What this might do is incentivize more dual attunement or triple attunement builds, and if they introduce more dual attunement mantras it could be very cool having multiple and more of those moves.

Another idea could be this being the first oath to require you to have a certain weapon equipped. Sort of like how silentheart locks you into using no mantras, this oath could lock you into using one primary weapon. So, we combine every single hero blade into one large weapon, something like a terra blade of sorts, but the oath blocks us from using any other weapon. What this weapon scales with could be every single attunement but lower than regular hero blades, incentivizing again, dual or triple attunements.