At the beginning of combat on your turn, you may sacrifice another creature. If you do, Dire Fleet Warmonger gets +2/+2 and gains trample until end of turn.
2020-06-23
While resolving Dire Fleet Warmonger's ability, you can't sacrifice multiple creatures to give it more than +2/+2 and trample.
2020-06-23
You choose whether to sacrifice a creature and which to sacrifice as Dire Fleet Warmonger's ability resolves. No player can take action between the time you make that choice and the time it gets +2/+2 and has trample, if appropriate.