[Ranger] Fiendish Mask Archetype

Welcome to the first in a series of ranger subclasses! There will be three new ranger subclasses available in the upcoming Ranger's Guide compendium, as well as updated reprints of three previously released rangers. I'm actually really excited for how they turned out. As always I spend hours designing and fine-tuning them so you can justify to your DMs they're balanced.

The ranger design philosophy used to be somewhat consistent: damage features at 3rd and 11th, defensive or utility features at 7th and 15th to coincide with a character's power level increase. Nowadays, with Fey Wanderer and Drakewarden in the mix, things certainly have smoothed out a little with more room for exceptions.

Fiendish Mask Design

This ranger is mainly designed to be very magical (like fiends!). Many of its features grant extra magic or casts of spells, or deal with spellcasting itself. This would be normally be great, but reliant on building out Wisdom which most rangers fall behind on. Other than that, it borrows several fiend traits.

Fiendish Mask Features Overview

• Fiendish Mask Magic - At 3rd level, the ranger gains spells like many others do, but these come with a unique benefit: the ability to cast them once each without expending a spell slot. Super helpful in any situation. Two of these spells (or wall of fire) don't require saves, so rangers can still get some benefit even if they don't increase their Wisdom score. Keep in mind that the ranger gradually grows stronger thanks to this feature's extra spell casts.
• Mantle of Devils - Also at 3rd level, the ranger gains some utility features: a boost to a Charisma-based skill for interactions (not the most useful, but flavorful), and devils sight that lets them see through magical darkness. This will combo well with darkness gained later on and also makes them very fiendish. Not quite as powerful as the Gloom Stalker's superior darkvision.
• Hellfire Strikes - This grants the ranger increased damage like all other rangers. Unfortunately, fire resistance is common so 11th level grants some resistance bypass (much needed if they're fighting fiends).
• Fiendish Resistance - this allows the ranger to swap between resistances - pretty standard defensive feature common with warlocks/sorcerers.
• Demon's Torment - this grants the ranger another spell, plus the option of casting it as a reaction to free up the action economy (and adds a flexible choice between hellish rebuke or fear). Very useful, but may be costly considering fear can normally target crowds.
• Magical Resilience - 15th level usually grants a defensive feature. Advantage on magic caused by creatures is excellent, but comes with some downsides. It uses a reaction and there's no way to tell whether it might be wasted on a success (used before the d20 is rolled). This is most comparable to Monster Slayer's Slayer Counter.