In Borderlands 2 each player class has 3 skill trees; Green, Blue and Red and for each character it will be named something different. In Axton’s case its Guerrilla (Green), Gunpowder (Blue) and Survival (Red). Within these skill trees are special abilities know as “Game changers” located in the middle of the Skill tree’s on each level with Axton and Salvador having an additional game changer in the fourth tier of two of the skill tree’s. These abilities only need one skill point to be assigned to give it the equivalent of 5 skill points assigned on normal skills within the tree.
The Capston is the final skill within each skill tree. This is generally a very powerful skill that turns your character into a kick ass power house, the caveat to this skill is only being able to use it one at a time.
You can see Axons complete Skill tree Here on the Borderlands 2 official site with Skill Tree Builder.
Axton’s Green Skill Tree: Guerrilla
Game Changer: Scorched Earth: this game changer adds a rocket pod to the sabre turret and basically every time the turret fires it is followed by a barrage of rockets. The rockets deal quite a bit of additional damage at 22 rockets per volly.
Capston: Double Up: Adds another barrel to the sabre turret, not only that it then equips the turret with Slag rounds so you get additional slag bonus when slaughtering enemies. +100% more turret guns
Axton’s Blue Skill Tree: Gun Powder
Game Changer: Longbow Turret: As the name describes, this game changer outfits the sabre turret with a longbow delivery system. What does that mean? Its basically being able to deploy your turret at any location you want instantly. Turret deploy range +10,000%, turret health +110%
Game Changer: Do or Die: Lets you use Grenades during Fight for your life.. Grenade damage +10%, Rocket launcher damage +10%
Capston: Nuke:Yes that says NUKE. When the Sabre Turret is deployed it creates a nuclear blast and gives damage to everything within its blast radius. Scared of Nukes going off to close to your head? Use Longbow to deploy it further away and quicker.
Axton’s Red Skill Tree: Survival
Game Changer: Phalanx shield: When deployed the Sabre Turret will deploy an energy shield around itself deflecting all enemy fire. If you are within the energy shield you can still fire outwards and kill enemies. Turret shields +1
Game Changer: Mag-Lock:With this game changer the Turret can be deployed in almost any position and any surface. This means you can deploy the turret on ceilings, walls etc.. +100% more sticky
Capston: Gemeni: Double Turrets.. yes you read correct, after you deploy your sabre turret you can deploy another one with Gemeni. The awesome part about Gemeni is if you have Plalanx shield then both turrets will have that capability, Rocket pods.. yup.. same deal.
Article from Gamersyndrome.com