Passively
One of K’ril Tsutsaroth’s minions is a lesser demon (Zakl’n Gritch, ranged minion) and thus the K’ril Tsutsaroth grind can result in receiving the Lesser Demon champion scroll.
Actively
Place a cannon in the Wilderness slayer cave, the slayer cave entrance can be found close to the level 19 obelisk or the Chaos Temple teleport on the burning amulet. Lesser Demons are located in the Wilderness, thus don’t bring any wealth that you are not willing to potentially lose. This includes cannonballs, try to keep trips short and match cannonball stacks you’re bringing with that. You may use either melee or range for killing Lesser Demons
Tips
The Arclight can speed up the kills substantially but does cost ancient shards, it is a personal choice if they are worth it for you.
