Runes | UNDECEMBER Game Guide
You can equip a Skill Rune to an unlocked slot and use it just like the existing Trigger Slots/Skill Slots. ※ You can change the hotkeys for Quick Slots through [Settings] - [Hotkeys] - [RM Quick Slot Skill 1 - 4].
Bosses | Diablo 4 Wiki
How can players get more Lair Boss Keys in Diablo 4?
Diablo 4 The Armory Guide | Epiccarry
Diablo 4 Armory guide! Learn how to save, load, and switch builds fast. Use 5 loadout slots per character for gear, skills, Paragon boards, and more. ✅ Epiccarry - Best Boost Service ⭐️
Skills won't change - Technical Support - Diablo 3 Forums
For Diablo III on the PC, a GameFAQs message board topic titled "cannot change skill during the battle?".