Sacrificial fusion

Sacrificial fusion (イケニエ合体, ikenie gattai) is a unique feature of fusion in Shin Megami Tensei III: Nocturne. This fusion can only be performed during full moon.

In a normal two-demon fusion, the resultant demon is always at a fixed level regardless of how much the ingredient demons have advanced. By adding a third demon which acts as a "sacrifice", the resultant demon will inherit more skills and 1.5 times experience the sacrifice has accumulated, and possibly gain higher level than its base level. (This also means the resultant demon will not gain any exp. bonus from a "fresh" sacrifice). If the demon created from sacrificial fusion has received exp., this bonus can be stacked if the said demon is used as sacrifice in the next fusion.

The drawbacks of this fusion are: 1, the resultant demon could gain too much level which surpass the protagonist's level, preventing the fusion to be performed. 2, since fusion accident has a higher chance to happen in full moon, making the result derail easier, but this can be offset by saving the game before performing the fusion.

Some special fusion requires a specific sacrifice, some may not mandate which ingredient to be the sacrifice, but the rule of exp. bonus still applies.