Kal'gerion demon

The fastest way to get there is Hoardstalker ring teleport.

Wear your best melee weapon and armor.

Because these creatures have high defense, Turmoil prayer and Scrimshaw of attack are useful.

Bring 3 overload, 5 prayer flask, 4 adrenaline flask;

Bring Dreadnip, it could be very useful.

Bring healing e.g. Excalibur, good quality food

Bring 1 Portent of life or death, and 1 house tab, just in case you are low health.

Don't need to worry its special, just tank it, soul split if needed.

Since the recent invention update, you can disassemble most of its drop. So don't bring pack yak, bring 2 Steel Titan.