Cassette Beasts

The first relationship level for all partner characters is unlocked by completing their personal quest, except for Kayleigh, whose first level unlocks after completing This Is The World We Live In and her second level unlocks after completing her personal quest I Ran So Far Away.

For the other relationship levels, as the player character battles alongside the partner, any experience points they earn are also counted as "relationship points". Once the player's relationship points with a partner exceed a level-specific threshold, then the next time the player rests with that partner in the Gramophone Café, a relationship level-up scene will trigger, increasing their relationship level and resetting their relationship points to 0.

Level up, Points required
0 → 1, ---
1 → 2, 1,512
2 → 3, 4,104
3 → 4, 7,992
4 → 5, 13,176
Dating → Romantic, 19,656

The number of red heart icons corresponds to the partner's relationship level. When a partner's relationship is ready to level up, their heart icons will be beating (in the Party menu). I think it is also required that each partner sticks with their signature monster tape to gain relationship points.

The first relationship level for all partner characters is unlocked by completing their personal quest, except for Kayleigh, whose first level unlocks after completing This Is The World We Live In and her second level unlocks after completing her personal quest I Ran So Far Away.

For the other relationship levels, as the player character battles alongside the partner, any experience points they earn are also counted as "relationship points". Once the player's relationship points with a partner exceed a level-specific threshold, then the next time the player rests with that partner in the Gramophone Café, a relationship level-up scene will trigger, increasing their relationship level and resetting their relationship points to 0.

Level up, Points required
0 → 1, ---
1 → 2, 1,512
2 → 3, 4,104
3 → 4, 7,992
4 → 5, 13,176
Dating → Romantic, 19,656

The number of red heart icons corresponds to the partner's relationship level. When a partner's relationship is ready to level up, their heart icons will be beating (in the Party menu). I think it is also required that each partner sticks with their signature monster tape to gain relationship points.