MarineAngemon is a rare Pixie Digimon that resides in the Net Ocean, a digital realm analogous to the deep sea. Its appearance is based on the clione, also known as a sea angel, giving it a small, pink, aquatic form with fin-like arms, bird-like wings on its back, and a long tail. Despite the Angemon suffix, MarineAngemon belongs to a completely different biological family from the standard Angemon species. It wears a golden Holy Ring around its neck, a detail that has led to speculation about a possible connection to other holy Digimon, though the ring's inscribed characters have never been deciphered. Despite being a Mega-level Digimon, MarineAngemon is physically very small, roughly the size of a small cat. In the Digimon Tamers continuity, MarineAngemon first appeared during the confrontation with the D-Reaper, where it chose Kenta Kitagawa as its partner. It was the only Mega-level Digimon that did not revert to a lower form when returning to the Digital World, thanks to its already diminutive size.

MarineAngemon has a gentle and pacifistic personality. It fundamentally dislikes combat and prefers to avoid violence whenever possible. It is a quiet Digimon that communicates very little, often only making a simple sound like Pu, and as Kenta has observed, it is a Digimon of few words. Nevertheless, MarineAngemon is loyal to its friends and willing to act when needed, applying its Mega-level power toward protective and supportive ends rather than destructive ones. Its primary motivation is to maintain peace and safeguard those it cares about, and it will fight only when it has no other option.

In the movie Digimon Tamers: Runaway Locomon, MarineAngemon is first seen with Kenta shopping for a birthday present for Rika Nonaka. When news of the runaway Locomon breaks, they join the other Tamers. MarineAngemon later takes part in the large-scale battle against the Parasimon that have invaded the real world. Despite being outnumbered alongside the other Digimon, MarineAngemon uses its abilities to destroy several Parasimon, contributing meaningfully to the defense. Its role in the story is that of a supportive fighter, using unique non-lethal techniques to assist the team.

The key relationship in MarineAngemon’s life is with its Tamer, Kenta Kitagawa. The bond between them is firmly established by the time of the movie, and MarineAngemon’s loyalty to Kenta is clear. It also works alongside the other Tamers’ Digimon, including Guardromon, Guilmon, and the other Mega-level partners such as Gallantmon, MegaGargomon, Sakuyamon, Justimon, and Beelzemon Blast Mode. MarineAngemon fits into the team as a calm, steady presence that provides both healing and combat support.

MarineAngemon shows little direct development within the movie itself, as its character is already established from the television series. However, the movie reinforces its reliability and its willingness to fight alongside the group when the situation demands it. Its growth throughout the series lies in the formation and deepening of its partnership with Kenta, and by the time of Runaway Locomon that partnership is solid.

The most notable ability of MarineAngemon is its special move Ocean Love, also known as Kahuna Waves. This attack involves releasing heart-shaped bubbles from its mouth. These bubbles have multiple effects: they can heal allies while removing negative status conditions, or they can damage enemies by bursting on contact and surrounding them with a burning pink aura. In some cases, the bubbles cause opponents to lose their fighting spirit entirely, effectively pacifying them without causing lasting harm. MarineAngemon is fundamentally designed for support and pacification rather than direct offense, yet its Mega-level strength makes it a capable combatant when necessary. The Holy Ring it wears is a marker of its potential connection to sacred Digimon, but its exact function is not explored in the movie.