A Green Imp is a small monster found in 600 A.D. in Chrono Trigger. They are very similar to the Blue Imps, except the Green Imps have more Hit Points.
Crono encounters Green Imps while traveling through Guardia Forest on his way to Guardia Castle.
While traveling to and from Guardia Castle and the Cathedral, Crono and his party encounter more Green Imps in the Forest. They also meet some in Truce Canyon on their way back to the Time Gate.
More Green Imps are encountered in Truce Canyon while Crono and his party pass through on their way to hunt down Magus.
After Crono's party acquires the broken parts of the Masamune, they head back to the Time Gate in the Canyon and battle more Green Imps along the way.
They encounter Green Imps in the Canyon again on their way to repair the Masamune and recruit Frog.