Sese Kitsugai

Sese Kitsugai (Japanese: 乞骸　セセ; Kitsugai Sese) is a character from the Len'en Project series of games, which are made by JynX, and their Ex form is the Secret Boss from Tangent's Undertale x Len'en fangame Len'entale. Sese was one of the candidate characters for a Len'en 2600 (see: Touhou 2600 series) game.

Character
Main article: Sese Kitsugai - Len'en Wiki

Sese is a gashadokuro (a.k.a. ōdokuro), a yōkai from Japanese folklore. While a gashadokuro is traditionally a giant skeleton made up of many smaller skeletons, Sese is human-sized normally. In the events of the Len'en game they debuted in, they wanted to find their own skeleton/corpse in order to become powerful (ideally gaining their true giant form). In the Extra stage of Reactivate Majestical Imperial (RMI, the 2nd game in the Len'en Project series), after the player has defeated the boss, Sese appears in their Ex form and adds 5 extra spell card attacks that the player needs to beat to finish the game.

In Len'entale, Sese found parts of their skeleton, allowing them to transform into a more powerful and more gigantic form than their normal form. The music that plays during their battle is their Ex+α theme from RMI, Those Dwelling in Unreality. Sese's and Sans' dialogue "voice" in the game is voiced by Tangent.

Spell cards
In Len'entale, Sese has 1 spell card attack that has 2 main phases. The spell card, while not having an official name, is based on Sese Ex's first spell card from the Ex+α stage in RMI, Piercing Bone "Rib Braver". No "greens" drop during this spell card. Taking a hit from rib bones takes 2 HP away from the player (as with the blocks/pipes from Yabusame's last spell), whereas a hit from the bullets takes the normal 1 HP.

Originally, there were going to be 4 phases, with the bullet circles part and the bullet circles + rib bones being separate, but while playtesting, Tangent thought that the bullet circles being its separate phase gives the player too much time to practice so when the rib bones get added, that (together) would not become much of a threat, so the circles alone exists in the final game only as the beginning of the second phase.