in this guide ill be showing you how to kill the armadyl boss, Kree'Arra. It has 1,000 HP and is level 650. hes kinda hard to kill but this guide will explain the right way and the not-so-right way to do it.
first, your inventory should look like this

you should wear some good range armor or mage. melee isnt the best idea.

use only about 1 prayer pot for the sara mages and pray melee for them.

when you have enough killcount, go in the right portal (highlited blue) for bandos and the left portal (highlighted red) for armadyl.

if ur ranging/maging from a distance it will range u and try to bring u up closer to it. the most it can hit you with protect from range on is 4. if u dont have protect range on, it can hit you for 69!and every time it ranges you, it drains your prayer by 5.

if youre protecting from range and ur 1 coordinate away from him, he can range you for 69 and melee you.
if youre standing 1 coordinate away from it and you have protect from melee on it hits you for 15 constantly

if you dont have any protect prayers on it can hit up to 69.

goodluck, and try not to die

*Jbird is the 1 who told me the information for this guide, i just made it. All credits to him*