Stormcaller is a Warlock subclass from the original Destiny (Destiny 1), powered by Arc Light. Below are its abilities and every choice in its skill tree, as listed in the game files.
Core abilities
Jump and then press again while in the air to activate Glide.
Chain Arc Lightning from your hands.
Deliver an electrocuting Arc melee strike at extended range.
Skill tree choices
Choice 1 (pick one)
A grenade that periodically damages enemies inside its explosion radius.
A grenade that calls down a focused lightning storm.
A grenade that chains bolts of lightning to nearby enemies.
Choice 2 (pick one)
Upgrades Glide for better directional control while in the air.
Upgrades Glide to provide an initial boost of speed.
Upgrades Glide to provide bonuses to both speed and control.
Choice 3 (pick one)
On casting Stormtrance, fire a bolt of lightning into the ground, creating a devastating shockwave under you.
Doubles your Stormtrance lightning's chaining capabilities.
Press to teleport during Stormtrance.
Choice 4 (pick one)
Your Thunderstrike chains to another nearby enemy.
Your Thunderstrike has greater range.
Hits with Thunderstrike charge your Super, Ability and melee energy.
Choice 5 (pick one)
Training focused on battle recovery and speed.
Training focused on battle recovery and toughness.
Training focused on toughness and speed.
Choice 6 (pick one)
When critically wounded, trigger a Pulsewave that boosts speed for you and your allies.
Incoming melee attacks fully recharge and intensify your Thunderstrike.
When cast with full grenade and melee energy, Stormtrance restores your health to full and drains slower.
Choice 7 (pick one)
Training focused on all attributes.
Training focused on raw speed.
Training focused on toughness at all costs.
Choice 8 (pick one)
Stormtrance charges faster when allies are near. When Stormtrance is active, nearby enemies take damage.
Enemies damaged by your grenades chain deadly lightning to nearby enemies.
Grenade kills recharge your melee. Melee kills recharge your grenade.
Grouped the way the game groups them: in each group you can have one option active at a time.