When a Kineticist uses the Kinetic Blade infusion, they create a temporary weapon and can make attacks with it for the round.
You form a weapon using your kinetic abilities. You create a nonreach, light or one-handed weapon in your hand formed of pure energy or elemental matter. (If you’re a telekineticist, you instead transfer the power of your kinetic blast to any object held in one hand.) The kinetic blade’s shape is purely cosmetic and doesn’t affect the damage dice, critical threat range, or critical multiplier of the kinetic blade, nor does it grant the kinetic blade any weapon special features. The object held by a telekineticist for this form infusion doesn’t prevent her from using gather power.
You can use this form infusion once as part of an attack action, a charge action, or a full-attack action in order to make melee attacks with your kinetic blade. Since it’s part of another action (and isn’t an action itself), using this wild talent doesn’t provoke any additional attacks of opportunity. The kinetic blade deals your kinetic blast damage on each hit (applying any modifiers to your kinetic blast’s damage as normal, but not your Strength modifier). The blade disappears at the end of your turn. The weapon deals the same damage type that your kinetic blast deals, and it interacts with Armor Class and spell resistance as normal for a blast of its type. Even if a telekineticist uses this power on a magic weapon or another unusual object, the attack doesn’t use any of the magic weapon’s bonuses or effects and simply deals the telekineticist’s blast damage. The kinetic blade doesn’t add the damage bonus from elemental overflow.
Since the kinetic blade is not a natural weapon, then it acts as a manufactured weapon. Then the Kineticist can combine it with the Energize Weapon infusion for extra damage:
Choose a manufactured weapon in your hand (not an unarmed strike or natural attack); if the weapon is a double weapon, you must choose one of its ends to receive this benefit. You imbue the chosen weapon with your elemental energy as part of an attack action, charge action, or full-attack action to add extra damage to each of your attacks with that weapon until the beginning of your next turn. Your attacks with the chosen weapon during that action deal 1d6 additional points of damage. At 7th level and every 6 levels thereafter, this bonus damage increases by 1d6 points. Blue flame blasts deal double this additional damage.
The additional damage is of the same type as the infused blast’s damage. This additional damage ignores spell resistance and doesn’t apply any modifiers to your kinetic blast’s damage (such as your Constitution modifier).
As long as the Kineticist accepts the combined Burn cost, that means they can make attack rolls using both infusions together.
Can the Kinetic Blade and Energize Weapon infusions be combined this way?
Best Answer
No, because of the action economy
Kinetic Blade and Energize Weapon are both form infusions which must be used as part of an attack action, charge action, or full attack action, which means they cannot normally be used together; a kineticist can only use one form infusion and/or one substance infusion on a single invocation of kinetic blast:
With the normal action economy you could only possibly make one of these actions on a given turn so that precludes you being able to invoke both infusions at once, and the kinetic blade only lasts until the end of your turn, so it's gone before you can use it in another attack/charge/full-round attack action.
What if I have extra actions somehow?
If you were to have access to extra standard actions somehow (such as granted by certain Mythic effects, for instance) you could conceivably be able to create the kinetic blade with a standard attack action and then make another attack action with it, applying Energize Weapon with the second action. This does require you to consider the kinetic blade as a "manufactured weapon", but the precise definition of that is contested. There doesn't seem to be specific clarification from Paizo on whether or not the kinetic blade is a manufactured weapon or not, but the similar case of the Warlock's mystic bolt was addressed in FAQ:
It looks like maybe a kinetic blade shouldn't be considered to be a manufactured weapon, as it is very similar to mystic bolt... but the whole manufactured/not-manufactured distinction is pretty muddy and awful. It seems like it was sometimes used as a catch-all to mean any non-natural weapon, but in others has a definition a little more in-line with standard English. In order for the system to make any sense, some common sense reasoning generally needs to be applied to determine which meaning is meant in context and whether or not an effect is applicable.
Personally, I'd rule that it's okay to combine the two effects if you've got the actions necessary to make it happen; there are worse things you could be doing with extra actions, and it would let you combine different blast types, which is cool.