Buy OSRS Aether rune
The Aether rune is a combination rune in Old School RuneScape. It counts as two runes at once: one cosmic rune and one soul rune. Any spell that needs a cosmic rune, a soul rune, or both will use just one Aether rune instead.
This makes Aether runes great for saving space. Players can cast Death Charge, Dark Demonbane, and summon thralls with only four rune types: aether, blood, death, and fire. That means a divine rune pouch can hold every rune needed for all three of those spells at the same time.
Aether runes are tradeable on the Grand Exchange. Crafting them yourself is a big job. It takes level 90 Runecraft, an aether catalyst, pure essence, soul runes, and the Magic Imbue spell at the Cosmic Altar. Combination runes also have only a 50% success rate unless you wear a binding necklace.
Buying Aether runes skips all that work. They are a smart pick for players who use thralls and other soul or cosmic spells in raids, boss fights, and Slayer tasks. Fewer rune slots means more room for food, potions, and gear switches.