Despite the fact that, let's face it, we KNOW Xavier is going to come back, he's currently being presented as Killed Off for Real
. Basic pattern recognition dictates that they'll come back, but just in case this one actually sticks it should stay.
After all, the point of the trope is a permanent death in a work where Death Is Cheap
. If we ignore instances where we assume they'll come back eventually, it seems like it undermines the point of the trope, you know?