More Infos from #Unknown :
It’s similar to Xingqiu / Yelan-type coordinated attacks, just without elemental application.
It’s like coordinated attacks, but the CRIT stats are taken from the on-field character. Not sure whether it benefits from Normal Attack / Skill / Burst damage bonuses.
The additional damage is not at Xianyun level, expect it to be lower
C1 gives a significant boost to the additional damage
ATK buff is triggered by Skill (E)
Additional damage is triggered by Burst (Q)
At C0, the buffs are mainly ATK + additional damage
C6 values are expected to be quite high
C2 / C6 are the major upgrades
Translation source:meowtews