Fiendish BowMaster

The Fiendish Bowmaster Is a ranger formed of hate and anger, The Fiendish Bowmaster can, unlike other rangers, cast spells, their spellcasting ability is derived from strength. The Bowmaster has, similar to other rangers, proficiency in ranged weapons. The bowmaster has advantage on attack rolls, str, and dex when in heated enviroments (ex:hot desert) They have disadvantage on str, attack rolls, and dex in cold enviroments. They have resistance to fire attacks, but take double damage to ice spells and attacks (ex:ray of frost) The Fiendish Bowcasters speed is 25ft, the Fiendish Bowmaster can cast ice spells, if they do, the attack does double damage, but they take that damage as well as the target. Upon choosing this subclass, you can switch a ability modifer (dex,int,cont,etc.) with str. 

Story: The Fiendish Bowmasters are hunters that have been banished to the infernal realms. These Fiends were banished for slaying divine demigods and gods. They hunt in the brutal wasteland that is the infernal realms. The Bowmaster could escape these lands however, through deception and power, can make it out. The Bowmasters dedicate their life to hunting only the best marks, even divine gods fear the Fiendish Bowmaster. They work together in cults, called flame rings, to hunt down marks. there are three main flame rings, the ring of souls, focused on killing beasts and extarcting souls from their dead mark. The ring of inferno, focused on burning the divine realms to the ground. The final, and biggest ring of them all is the ring of death, this ring dosent have true motives, their only desire, is to burn and kill, leaving death and destruction in the path of this ring.

Infernal Hate

At 4th level, Twice per long rest, you can, as a bonus action, summon true hatred. All attacks, even monster attacks, even your party's attacks, do double damage For the Duration of the round. (if your last in initative, the duration is the next round.)

Bolt Of Flame

At 10th Level, You can, as a action use this ability once per long rest (twice at level 12) The ability can hit up to 5 targets, they each must make a dc 20 dex saving throw, if they succed they take half damage. When using this attack, you summon the boiling lava from the infernal plane itself, and fire bolts of magma at targets, EACH of these five bolts does 1d8 fire damage.

Call Of The Infernal Plane

At 15th level, Once per two long rest (once per long rest at level 18.), as a bonus action, you can open a rift to the infernal plane, a demon will arise, and grant you immense power. ALL attack rolls you do on your turn have +5, all attacks you do an additonal 2d12 damage.

Demonic Inferno

At 20th level, You may use an action (so yes, you can double this with infernal hate) to transform your body into a demonic god and wreak havoc on two enemies. EACH target suffers from 10d20+10 fire damage, AND 8d12+30 damage of a type of the player's choosing. After using this attack, your hp drops to zero, you have pushed your body to it's limits, for the death saving throw after you drop to zero, you MUST make, with no advantage, a 18, 19, or 20 to succed, you have three tries.