Not invincible, but suppress upon entry. Its not op cause its a stationary object, its not like the titan is running around shutting abilities down with a dome on his head. Lol people stop what they are doing to go and try to take on a defender titan cause most times they think they are a sitting duck and don't fear them, and that what I think the op is trying to address here. I main defender and there are ways to kill one without using abilities or a super even with armor of light on....