Do you have to hold an arcane focus in your hand to use it? Can you wrap it around your wrist or embed it in the pommel of your sword? You need a free hand to manipulate or hold a material component or focus. Some focuses are meant to be worn such as emblems and amulet holy symbols.
Arcane focuses specifically need to be held, the general rules don't account for them being embedded in other objects or worn.
— Dan Dillon 👥 (@Dan_Dillon_1) January 19, 2020
That said, as a DM I'd allow a wizard to wear their crystal focus around their neck as long as they have a free hand to touch/manipulate it when casting.
— Dan Dillon 👥 (@Dan_Dillon_1) January 19, 2020
For my game they have to use normal spell components to cast spells from levels 1-10.
Only until they reach Level 11 will they be learned, and have enough magical power to create an arcane focus.
Also, I will use 1st edition’s Item saving throws since 5e’s take is a joke. So, the arcane focus has a chance to break just like anything else.
I’ve played a character whose arcane focus were gloves as runes. He also had an arcane focus tattoo on one hand. I’ve also played a wizard , whose hat was his arcane focus.
What about divine foci?
I could see a cleric or paladin having a their holy-symbol as a peice of julery, or as a graphic design on a sheild or vestiments.
Could any of those work?
How does this apply to an artificer who uses their tools as their focus, but also the armor of tools infusion?
Just discovered the Ruby of the War Mage, XGtE pg138. It’s a common magic item that binds to a melee weapon and makes it an arcane focus. Awesome.