Bowser

Bowser is Mario's long time archnemesis and the main antagonist of The Paper Mario Super Show. He first appeared in the episode Bowser is back, where he halted Mario, Vivian and their new teammate Kooper while they were taking a walk. He then engaged in a battle against Mario and Kooper. He was then defeated at the hands of the two protagonists. After the episode Bowser is back, Bowser started to appear in episodes as an antagonist. His Koopa Troop forces on the show grew stronger as the show continued.

Appearances
Bowser appears as a villain in most episodes.

Bowser is back (debut) (antagonist)

Fransisco From Far Away (antagonist)

The Koopalings Bodacious Return (antagonist)

Midbus Returns (antagonist)

F.U.F.F. is Born (antagonist)

The Quest for The Fire Stone (cameo) (antagonist)

Relationship with other characters
Mario

Bowser and Mario are bitter enemies since Super Mario Bros, so they share bad chemistry.

Luigi

Bowser and Luigi also share bad chemistry, since Luigi aids his brother Mario in some of his adventures.

Peach

Bowser falls for Peach, but Peach doesn't fall for Bowser. They also share bad chemistry on the show. This is most likely because Peach defeated Bowser in Super Princess Peach.

Mushroom Pack

Bowser doesn't like Mario's party members. He seems to dislike Kooper more then Vivian, since Kooper defeated Bowser along with Mario in the episode Bowser is back.

His children

Bowser seems to like his children on the show. This is implied because he was happy to see the Koopalings again in the episode The Koopalings Bodacious Return (This information is now invalid since Shigeru Miyamoto has confirmed the Koopalings are not Bowser's children.). He also shares good chemistry with Bowser Jr.

Koopa Troop

Bowser's relationship with his army on the show is currently unknown.