Runic Thief

As many adventurers and crafters, you decide to explore the intriguing possibilites offered by runic magic.

When you chose this archetype at 3rd level, you acquire a pebble-sized crimson runic stone of 100gp value which grants you the ability to use magic.

You need to hold the stone in one of your hand to cast spells. If you do not have the stone, you may cast spells at the cost of 1 Health Point per level of spell, by inscribing a runic cercle with your own blood on your hand or on a glove.

If you lose the stone, you may buy one again for 100gp.

Spellcasting
Cantrips. You learn two cantrips: mage hand and one of your choice from the bard spell list. You can learn another bard cantrip of your choice at 9th and 13th level.

'Spell Slots. 'The Runic Thief has one less spell known and one less spell slots per spell level than the Arcane Trickster (see the Arcane Trickster Spellcasting table p98, disregard cantrips). Everything else works in the same fashion with the exception that

the Runic thief may only know spells from the illusion or divination spells on the bard spell list.

Spellcasting ability Same as the Arcane Trickster.

Master of the Runes
Starting at 17th level, you are now able to see magic, as if under a permanent Detect Magic spell.

Furthermore, you get advantage on any saving throw made for a spell cast by a spellcaster that you can see or hear.