Level 90 Slayer
and have started Mourning's Ends Part II
is required to kill the Dark Beast (except in Kuradel's Dungeon). No slayer equipment is necessary. Dark Beasts have both Melee and Mage attacks. However, they will only use their Mage attacks if you attack them first, this is a one off attack providing you are within melee distance for its next attack, if you are not it will continue to use magical attacks. While the magic is weak in terms of its max hit, it is accurate. These creatures will always remain aggressive as well.
Charm Drop Rates
These are difficult to get to. Effective is to use a prayer boosting gear and use protect from melee. Dark beasts have very high range defence. It is more than common to melee them with prayer armour on. Ranging them is only recommended at very high Ranged. (90+)
From a darker dimension.
Dark bow, Dragon med helm, Starved ancient effigy
Coins (52-3000), Grimy herbs (1-2), Black battleaxe, Black hatchet, Black 2h sword, Adamant sq shield, Rune 2h sword, Rune battleaxe, Rune chainbody, Rune full helm, Rune sq shield, Rune kiteshield, Steel arrow (150), Rune arrow (42), Death talisman, Attack potion (3), Blood rune (7), Nature rune (67), Death rune (3-45), Chaos rune (10), Air rune (47), noted Silver Ore (100), noted coal (619), Shark (1-2), Gold charm, Green charm, Crimson charm, Blue charm, Ferocious Ring (5) (Kuradal's Dungeon Only), Fellstalk seed (2)