I know! Mass slingers! They'll never expect THAT!
Then, evolve into Middle Marignon, and all the slingers will automatically upgrade into Crossbowmen! If you do
during the first turn of battle, the crossbowmen will start with volley of slingstones fired from crossbows in addition to their normal quarrel shot!
Somehow I feel that whatever strategy he is using, slingers are only mentioned in the "do not use" category.