Emilia is familiar with the concept of «return by death,» which is a belief that someone will be resurrected after death. According to the belief, someone will be reincarnated into a new body and live again. It is important to note that there is no scientific evidence to support the belief in return by death.

Who else knows Subaru’s return by Death?

Subaru’s return by Death is a concept found primarily in the Japanese visual novel and anime series Re:Zero − Starting Life in Another World. It refers to a phenomenon in which Subaru Natsuki, the protagonist of the series, is able to rewind time by dying and restart the day from the previous «checkpoint». Other characters who are aware of this concept include Emilia, Puck, Beatrice, Rem, and Ram.

What happens when Subaru says return by Death?

When Subaru says «Return by Death,» he is referring to a concept in the Japanese light novel and anime series Re:Zero. It is a form of time travel that Subaru gains the ability to do after being killed. With this power, Subaru can return to a point in time, undoing any damage he has done since that point, allowing him to make different choices and try different strategies. This is a very useful ability, but it comes with a cost: for every time Subaru dies, his ability to return by death is decreased, so he must be careful to make the right decisions.