LieutenantAn ability word has no rules meaning of its own. It groups abilities with similar themes; the text following it explains this card’s effect. (CR 207.2c) — At the beginning of combat on your turn, if you control your
commanderA designated card for a Commander deck, governed by the command-zone, color-identity, and Commander rules. (CR 903), target nonlegendary creature you control gains
myriadMyriad is a triggered ability that may also create a delayed triggered ability. “Myriad” means “Whenever this creature attacks, for each opponent other than defending player, you may create a token that’s a copy of this creature that’s tapped and attacking that player or a planeswalker they control. If one or more tokens are created this way, exile the tokens at end of combat.”
If a creature has multiple instances of myriad, each triggers separately. (CR 702.116) until end of turn. (Whenever it attacks, for each opponent other than defending player, you may
createTo create one or more tokens with certain characteristics, put the specified number of tokens with the specified characteristics onto the battlefield.
If a replacement effect applies to a token being created, that effect applies before considering any continuous effects that will modify the characteristics of that token. If a replacement effect applies to a token entering the battlefield, that effect applies after considering any continuous effects that will modify the characteristics of that token.
Previously, an effect that created tokens instructed a player to “put [those tokens] onto the battlefield.” Cards that were printed with that text have received errata in the Oracle card reference so they now “create” those tokens. (CR 701.7) a token copy that's tapped and attacking that player or a planeswalker they control.
ExileTo exile an object, move it to the exile zone from wherever it is. See rule 406, “Exile.” (CR 701.13) the tokens at end of combat.)