The level 84 warriors use crystal halberds and are weak to fire spells, while the level 89 warriors use crystal bows and are weak to crush.
Killing the elves in Lletya (this requires Mournings End Part 1 to be started) is more convenient than killing those in the Elf Camp as there is a nearby bank and altar, which is upstairs in the house where Arianwyn is located. However, only the elves in the Elf Camp drop charms. After completing Deadliest Catch a deposit chest is available south of the camp. Fishing spots and rabbits are nearby for replenishing food.
Elves live far longer than humans, and those that choose a military life have decades to hone skills that humans must train in months. As a result, elf warriors are among the most dangerous defenders of any town or city in RuneScape. They wield vicious pikes and crystal bows, but are weaker in the face of stabbing attacks.
Knowledge Base, Game Guide
Slayer Strategy
An altar on the first floor. The ladder is located north of the bank.
Some lower levelled players maybe find that the safest method is to use range or mage and use the fences and benches as safe spots. Be reminded that the elf warriors with pikes have a halberd's reach.
An alternative location for this slayer task is the Elf Camp. This area has a fireplace as well as a fly fishing spot. Players can ultimately kill the elves there and stock up on their food supply by simply fishing. Note that the elves do not drop teleport crystals here.
This is one of the units to have been copied to FunOrb into Armies of Gielinor, although they are 2 different elf warrior units: elf archer and elf pikeman, in RuneScape they are still both called "Elf Warrior".
Chaeldar is apparently "Irritated Intensely" by elves and says "Slaughtering them is definitely a good thing". Sumona also seems to dislike the elves saying that "Their dedication to trees, bushes and music is an affront to me."
References
^Only elves in Lletya drop crystal teleport seeds. On rare occasions, a seed with one charge may be dropped, as opposed to an uncharged seed.