That time I got reincarnated as a slime

Treyni the dryad, protector of the Great Forest of Jura, asks Rimuru to fight the Orc Lord and his 200,000-strong army of orcs before they can destroy her woodland home. To do so, Rimuru will need help--but the only help around are the lizardmen, and after Rimuru's last clash with one of their leaders they might not look so kindly on him.