Athena is from Valentia.
- Athena mentions that she comes from another continent, it's probably a part of Valentia. It's close enough that pegasus knights can fly there.
The Falchion Marth gets in chapter 24x is the Parallel Falchion
- After wasting Grima, Naga sealed away the Parallel Falchion because they only really needed one. Gotoh sent Marth to the future to claim the weakened blade as a desperate last resort against Medeus.