Wait so his past life Parents got summoned to the same world? if so then why did his sister not get summoned/ reincarnated as well it would have been a good plot, to where his sister is summoned in that world and they meet because he is the only that can speak Japanese in that world and talks to his sister and tells her what happen.also how long has it been in his world? its been 4 years in that one but is time still going on in that one, or is is slowed down to like 1 min in that world is a year, in the one he is in rn?