Pigmon

While most creatures the expedition to the Lawless Monster Zone were vicious, Pigmon was not. It helped the injured sole survivor by giving him food it found and led the Science Patrol to him when they arrived on the island. When Red King attacked, Pigmon distracted the creature while the Science Patrol escaped, but Red King killed the creature by throwing huge rocks at it, crushing him to death. Later, Pigmon (along with Telesdon and Dorako) were resurrected by Geronimon as a warning to humanity, Pigmon warned the Science Patrol of Geronimon's plot to attack Earth with an army of 60 monsters under his control. The Science Patrol were able to destroy Telesdon without much effort, but after one of the members, Ide (Ito in the American version) is nearly killed by Dorako, Pigmon distracts the monster and is killed again by Dorako.

Powered
Pigmon's episode appearance and role were both very similar to the one of his debut in the original Ultraman TV show, again befriending humans stranded in a valley infested by monsters (ironically starring the monsters, Red King and Chandrah,) but is allowed to survive at the end of the episode this time.

Ultraman Max
In this series, Pigmon is sent by its species from another planet to live on a mysterious island ("Subject Phantom" according to DASH.) The Island sealed away Red King underground a long time ago and sent Pigmon, as well as two monsters named "Salamadon" and "Paragura" to act as guardians to both the island and to keep Red King from awakening. Pigmon quickly befriends Kaito, the host of Ultraman Max until both Kaito and Pigmon were knocked unconscious and a tomb keeping Red King is desecrated. Red King awakens and attacks, killing the two guardian monsters, then turning to Pigmon in hopes of killing it too. Kaito transforms into Ultraman Max and after a lengthy battle, destroys Red King. Pigmon then bids farewell to Kaito and Team DASH before turning into a stone statue to make the island disappear and not cause any further confusion.

The same Pigmon later returns towards the end of the series, where it warns Team DASH that Red King has returned "mysteriously" (in fact, it was an Alien Shama that opened a dimensional portal by accident that released both Pigmon and Red King.) Once Pigmon tries to fight the disguised Alien Shama, Shama hits it with a dimensional ray guy, but its atoms are mixed into Elly (an android member of Team DASH) and become amorous to Kaito (leading to confusion among both DASH and fans of the series to question where this Pigmon was male or female.) In the end however, Pigmon sacrifices itself by throwing itself into Shama's dimensional weapon separating his atoms from Elly's body and into another dimension while Red King is destroyed once again by Ultraman Max. It's also hinted that some of Pigmon's personality is still left behind in Elly's body at the end of the episode.

Pigmon is also given the ability of telekinesis in this series as it is able to speak to both humans and the guardians of the island in their minds by waving his arms in a circular fashion.

Mega Monster Battle: Ultra Galaxy Legend The Movie
In this film, Pigmon has befriended a temporarily banished Ultraman Zero, who is training with Ultraman Leo. It is also because of Pigmon's role in the film that Ultraman Zero learns about what it means to be an Ultraman, and thus leaves with that knowledge to face off against Ultraman Belial.