Ultraman Jack teams up with the youngest, and yet most powerful (at the time) Ultraman, Mebius to defeat Deathrem. I'm rusty on the previous aliens the various Ultras have fought (there's a lot) so I am not sure if this is one of Jack's foes from his series. Hideki Go rocks, though.
they sure play fast and loose with the "three minute" warning for the color timer in some Ultra episodes. which I always thought should never have been an actual set time. should be more of how much energy the Ultra has used. and Ultras like Seven didn't even have that weakness.