Fellslayer Ranger
Fellslayer rangers are relentless hunters of titanic foes, trained to track, evade, and fell creatures many times their size. Having a deep understanding of colossal adversaries, they excel in fighting giants, dragons, and other massive threats.
Level 3: Titan tracker
You gain proficiency in one of the following languages: Draconic, Primordial, or Giant.
When you make an ability check to track or recall information about a creature of size Large or larger, you can add your proficiency bonus to the check. This bonus is doubled at 9th level.
Level 3: Titan’s Foe
You always have the Enlarge/Reduce spell prepared, and it does not count against your number of spells prepared.
You can cast Enlarge/Reduce on yourself without requiring concentration. When cast this way, the spell only changes your size category, and you do not benefit from the spell’s other effects. This effect lasts for up to 1 minute. You can use this feature a number of times equal to your Wisdom modifier (minimum of once), and you regain all expended uses when you finish a long rest.
Additionally, once per turn, when you hit a creature larger than you with a weapon attack, you can add 1d6 bonus damage to the damage roll.
Level 7: Giant’s Might
When you use your Titan’s Foe feature, you can choose to target a creature other than yourself with the Enlarge/Reduce spell. When you do, you can also cast Hunter’s Mark on that creature without expending a spell slot, as part of the same action
A creature targeted this way has its size category changed, but gains no other effects from the Enlarge/Reduce spell. Both Enlarge/Reduce and Hunter’s Mark share a concentration slot when cast in this way, and the Hunter’s Mark is still applied even if the target succeeds on the saving throw.
Level 11: Nimble Swiftness
Your agility allows you to outmaneuver even the largest of foes. While fighting creatures larger than you, you gain the following benefits:
Slip Through. You can move through the space of creatures larger than you without penalties and climb them as though you had a climb speed equal to your walking speed.
Small Stature. While occupying the space of a creature larger than you, you gain half cover and can attempt to hide while obscured by them.
Evasion of the Mighty. You have advantage against saving throws caused by creatures larger than you, and their opportunity attacks against you are made with disadvantage.
Level 15: Titan Slayer
When you use your Giant’s Might feature to cast Enlarge/Reduce on an unwilling creature, that creature has disadvantage on the saving throw. In addition, the target takes a penalty to the saving throw equal to the number of size categories it differs from Medium. For example, a Small creature would take a –1 penalty, while a Huge creature would take a –2 penalty.
Additionally, you gain a bonus to weapon attack and damage rolls against creatures larger than you. This bonus equals your Wisdom modifier (minimum of +1).