I know if a character has Mystics, and does not cancel his TA, and deals himself damage, he'll take unavoidable damage as well for Mystics.

This scenario came up last night at the tourney I was running:

But what about Mind Control?

Player A was playing a Redeemer's theme team, and used the Thunderbolts ATA card so that his Thunderbolt keyword figures could use the Mystics TA.

Player B was playing an Asgardian theme team, and he used Mind Control against one of the Redeemers. He then used the mind-controlled figure (figure 1) to attack a figure (figure 2) that had the Thunderbolts ATA card assigned to it.

Would figure 2 deal Mystics damage to the mind-controlled figure 1?

The way I ruled it:

Since Player A didn't announce he was canceling his Thunderbolts ATA/Mystics TA on figure 2 when Player B declared that he was using the now mind-controlled figure 1 to do an attack against figure 2, figure 1 would take Mystics damage.

Is this correct?

The player can choose not to use Mystics to retaliate on his own figure.

Mystics does not care if the attacking character is friendly or opposing.

So if there is any potential that your Mystic might be damaged by one of your own characters (Mind Controlled or otherwise), you need to cancel that TA like you would cancel any other TA (AKA at the beginning of an action, remains cancelled for the rest of the turn, and so on).

Thank you! So I ruled it right, but wanted to be certain if it happens again in the future.

And for a Mind Controlled character it is friendly to your force and opposing to the other force for the duration of the action it is assigned.