4* Stone Blade - Charge attack launches a wave of earth spikes in a line
5* Earthrender - Charge attack launches a wave of earth spikes in three lines Or wave of earth spikes in one line, and aoe spike field around self on swing.
Full normal Damage (Higher base than avenger/faust damage)
Specialty - Immunity to interrupt, also might either have +damage, +hp, or Med-high chance of stun baseline
While wielding this weapon, you can't be knocked out of attacks or charging. I'm not sure how many people would actually use the idea of the weapon, due to the idea being pure normal, but the thought of having mega-armor or the like and not being able to be knocked out, might be a very viable choice versus all the other weapons that exist, given the fact that if you don't get knocked out, you will get your hits in even if struck, removing some of the timing issues the weapon has versus it's variants.
I'm not sure if this would really be necessary. The 4* weapon in the Troika series, the Khorovad (sp?) already has an earthy charged attack where rock spikes shoot up all around you (in addition to the massive overhand swing all of the previous weapons in the series did) and it's already got the all-normal-damage, hard to interrupt, heavy hitting angle going on.
And that's just the 4* one. Imagine what the 5* one will do when we get it. I'm guessing it will involve even more earth flying all over the place.