His time spent in Toki Toki City in Xenoverse implies he would help out with the Time Patrol, because Patrolmen have to stick together. But only if the opponents are those he's capable of fighting against, because he's a coward.
Also, the fifth slot would presumably be taken up by an avatar. It's the most fitting given the theme of DBO, Xenoverse, Heroes, etc.
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Anyway, update for GDM3. Probably the most lackluster update in a long time. Absolutely nothing new beyond what they already spoiled. It's almost all recycled Majin Buu material with Bibidi, Babidi, Buu and the Kaioshins (as well as a sprinkle of BOG, DB and GT).


Base form Trunks: Future for DNA:
Time Kaioshin's attack is Time Judgement.
BUT, that doesn't mean GDM3 doesn't have good things. We get a little bit more of the commercial, which will be Beerus and SSG Goku, as well as SS Bardock: Xeno and transforming Mira:
https://www.youtube.com/watch?v=GAlkLeY8Ifc
As you can see in the PV, lots more DBO designs being reused, and not just for the Time Breaker Majin girl. We also get at least an "Akkuman" baddie and the Red Pants Army's General Bon (assuming he keeps the name). Just as with the various extra characters Babidi enslaved a few sets back though, I imagine none of these will get cards though, so I'll have to wait for the videos and browse them for names and attacks I guess.
One of the SECs appears to be a transforming Mira, so I guess we'll finally get a form name. The other is guessed to be SS3 Bardock: Xeno. Feels like a waste to me since V-Jump is releasing him.