Okay he's my theory of why we saw what we saw at the very beginning of the series:
Jeha's father finds out about Mongryong's existence and he probably wants him dead, so Jeha fakes Mongryong's death (but Mongmong's not aware of this and takes it as betrayal), so when Jeha is done faking his death he sends his men to rescue Mongmong but oops too late.
Okay he's my theory of why we saw what we saw at the very beginning of the series:
Jeha's father finds out about Mongryong's existence and he probably wants him dead, so Jeha fakes Mongryong's death (but Mongmong's not aware of this and takes it as betrayal), so when Jeha is done faking his death he sends his men to rescue Mongmong but oops too late.