For skewer it can easily be adjusted and should be more like calico dash but really only have an very narrow target. Like unless they are literally on top of each other, it will only hit one person. Probably about as wide as Talon arrows. Numbers can always be adjusted too later on if its doing too much. Also, this kit doesnt really have any defense really. So dashing seems to be his thing. Dash in with Skewer (lunge way better name) techniques dash away and just always moving and hard to hit.
T3 techniques doesnt fit the ability. So, i would remove it. And honestly all of those are strong. Ide probably make t1 jsut an extra stamina bar, then bump the other two upgrades up to t2 and t3.
If you really like it, Maybe put it on t3 skewer instead, remove t1 and drop the other 2 down. They are a little weak as far as upgrades go but the ability has insane scaling so thats ok.
And my suggestion for Coup stands. My version (or rather the smite version) still does exactly that but is more fitting. it would be something along the lines of:
enter a battle trance, reducing in coming damage as you focus on your targets. You can use your primary 5 times while in this trance, firing a bolt of energy with each flick with extended range and pierces targets. Cannot hit (or ignores) npcs. The bolts can hit up to 3 heroes each. When the channel ends, dash/lunge/teleport (wording) to each target hit and perform a moulinet.
t1 2 extra bolts
t2 same but without the area effect damage
t3 same but without the area effect damage
Seriously, watch this. Go to 3:18 seconds to skip to ult:
Tsukiyomi ult