New DE Troop:ShadowWrath

Hi!Today I thought about a new DE troop called the ShadowWrath.Before you start screaming that this is useless,well,the ShadowWrath has a ability that makes him invisible.That ability upgrade whit the troop.
It`s stats time:

Lvl 1:
Training cost:395 DE
Training time:5 minutes
Damage:150
HP:255
Speed:20
Housing space:5
Invisibility time:3 seconds
Favorite target:Everything
Targets:ground

Lvl 2:
Upgrade cost:1.000 DE
Upgrade time:2 Days
Training cost:405 DE
Training time:5 minutes
Damage:160
Hp:262
Speed:20
Housing space:5
Invisibility time:8 seconds
Favorite target:Everything
Targets:ground

Reference art:
Attachment 79567
The ShadowWrath is the guy in the middle.
PS:When he is invisible he ca not be attacked by the Towers/Cannons/Bombs.

Good idea mate, but how high would you be able to upgrade the troop what graphics change would be applied when you get the troop to a high level and how would they move?( i.e ground or air) I admit the idea is good but there are a lot of un answered questions P.S thank you for the reference art.