Help

the +atk -res seems better to me due to the fact that most mages in arena are blue and they would kill her with neutral res anyway and having the neutral def means that she can duel a bit more reliably before getting into desperation range and killing everything by herself.

The difference between the atk and spd boons is minimal imho in Ayra's case. You ofc want speed because she is based around high speed, but she is already fast enough to double most units and proc her weapon effect on basically everyone even with neutral spd.

I'd go for the RES bane. Slap a SPD seal or slaying edge refinement if speed is a problem for you. Ayra is too good so it won't matter much.

If you're going for a DC set use the +speed one. If you're going to use a stat boost in your A skill then I'd say the +attack could be better(the +speed could still be better against speedsters but the -res would be better vs most melees).

-def bane hurts her melee potential. +atk-res would be my recommendation.