I was watching a marth lose to a ganon and learned/realized something...
Db as a landing option to beat shield grabs. Not really beat, but hit them out of their grab. Since Marth's aerials all have atrocious landing lag need the ground, aerial db1 to landing db2 (continue if you get the hits, stop after 2 hits, or connect the whole thing on shield using downward version to try for shield poke around) may be his saving grace to getting out of landing traps.
There's also the classic db1 stall and b-reverse shield breaker, but neither help when you're right about to land in front of a shielding opponent.
Db as a landing option to beat shield grabs. Not really beat, but hit them out of their grab. Since Marth's aerials all have atrocious landing lag need the ground, aerial db1 to landing db2 (continue if you get the hits, stop after 2 hits, or connect the whole thing on shield using downward version to try for shield poke around) may be his saving grace to getting out of landing traps.
There's also the classic db1 stall and b-reverse shield breaker, but neither help when you're right about to land in front of a shielding opponent.