Currently, depending on your sprite, you get 3 different skills to work with. That's 9 different skills you can choose from (27 counting ultimates). I was thinking we should maybe have 2 extra skill slots: one dependent on your equipped shield, armor, or weapon (you can pick which skill you want, for some shields/armor/weapons there won't be a skill (every armor and shield and weapon would be way too much)), and one that you directly equip Skills into. You can pick what goes into the shield/armor/weapon slot by clicking an already equipped armor, shield, or weapon and clicking "Use Skill". It'll be added to your fourth slot (the items bar will be moved back 2 numbers) and you can use it whenever it's not on cooldown. Cooldowns from the skills will be independent from sprite skill cooldowns, but will share the cooldown with your other skill. You can pick what goes in your fifth slot by equipping a Skill. You can get skills by using a Skill Token. These can be obtained from: Mission Rewards (probably rank, MAYBE once-per-knight only for prestige), Basil at the clockworks terminals in the Arcade, and maybe a special vendor in the Bazaar that will sell basic, low level skill tokens. When you use a skill token, it will bring up a screen with any number of skills on it. You can pick ONE to equip in your fifth slot. Afterwards, the skill token disappears.

Here are some ideas for skills:
Protoquake (Proto Shield)
6-10 damage
20 second cooldown
The user smashes the ground with their shield, creating a small earthquake that deals the skill's damage to any enemies within 5 tiles of the user.

Tidal Wave (Leviathan Blade)
90-110 damage
30 second cooldown
The user swings the blade, causing waves of water to be released from the blade and dealing damage to enemies in the 90 degree angle the user is facing, and within 10 tiles.

Hyper Speed (Swiftstrike Buckler)
N/A damage
45 second cooldown
The user embraces the full power of the buckler, allowing them to move as fast as someone with a Speed powerup on for 5 seconds.

Call to Arms (Cobalt skill token)
N/A damage
Can only be used once per level
The user summons 2 allied mecha knights to join their cause.

Unload (Antigua line)
3 star: 15 damage per bullet, 4 star: 35 damage per bullet, 5 star: 55 damage per bullet
30 second cooldown
The user quickly pulls out the Antigua (if not already out), fires 3 shots rapidly, then puts the Antigua away and draws whatever weapon they were wielding before. The bullets have a small spread. The damage type dealt is dependent on the gun used (Silversix = elemental, Gilded Griffin = piercing, etc.)

Whirlwind (Cutter/Striker)
Cutter: 15 damage, Striker: 20 damage
45 second cooldown
The user spins so fast that they create a whirlwind that damages enemies. If the Cutter is used for this move, the whirlwind lasts 3 seconds. If the Striker is used for this move, the whirlwind lasts for 4 seconds. Each second an enemy is in the whirlwind, it deals the skill's damage. For the first second of the move, the user is forced to stand still. The whirlwind stays where the user cast it.

Poisonous Whirlwind (Vile Striker line)
Vile Striker: 35 damage, Dread Venom Striker: 50 damage
40 second cooldown
Does the same thing as the Striker version of Whirlwind, but with more damage, the whirlwind lasts 5 seconds, the cooldown has been reduced by 5 seconds, and enemies are poisoned if they are hit twice by the whirlwind.

Vicious Whirlwind (Hunting Blade line)
Hunting Blade: 50 damage, Wild Hunting Blade: 65 damage
40 second cooldown
The same as Poisonous Whirlwind, but with more damage and no poison effect.

Aprocean Regeneration (Obsidian Edge)
2 pips per second
60 second cooldown
Aprocean tendrils pull you under the ground for 6 seconds, healing you by 2 pip every second. Afterwards, you reappear above the ground, poisoning you and all the enemies in a 3 tile radius. The enemies are poisoned for 15 seconds, while you are poisoned for 2.5 seconds. Allies are unaffected. The user cannot be seen or attacked by enemies while they are under the ground.

Celestial Storm (Celestial Saber)
N/A damage
25 second cooldown
Burns all enemies within a 5 tile radius of the user.

Sentry Stance (Autogun line (excluding the tortodrone guns))
2 star: 5 damage per bullet, 3 star: 8 damage per bullet, 4 star: 10 damage per bullet, 5 star: 15 damage per bullet
Only usable twice per level, 60 second cooldown
While under the effects of this skill, the user is not allowed to move and can only use Autogun-type weapons. Holding down the attack button fires bullets at a rate of 3 per second. The skill lasts for 15 seconds, and cannot be canceled by anything. If shocked, you'll periodically stop firing instead of cancelling the skill altogether.

Vitality (Vitasuits (Vitasuit, Vitasuit Plus, Vitasuit Deluxe))
N/A damage
Passive Skill
This skill is a passive skill and thus cannot be activated manually.
The user constantly regenerates health. The health regeneration depends on the armor:
Vitasuit: 1 pip every 45 seconds
Vitasuit Plus: 1 pip every 30 seconds
Vitasuit Deluxe: 1 pip every 15 seconds

Elemental (Sealed Sword only)
N/A damage
May only be used twice per level, 60 second cooldown
The user's Sealed Sword becomes enchanted with a random status effect for 30 seconds. This effect is dealt to monsters whenever you hit them with the second attack in the sword's combo. It can be enchanted with any status effect except for curse and sleep.

Energy Barrier (Cobalt skill token)
15 damage
Only usable twice per level, 35 second cooldown
Creates a barrier in the direction the user is facing. If a monster walks into the barrier, they receive 15 damage. Players are unaffected by the barrier.
The barrier itself is a wall that is about 5 tiles long.
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This would take a while to code but would be a very fun addition to the game. If you actually read this far into the post, you probably should do something else with your life because this was absurdly long. My fingers hurt. I probably should stop typing now. Enjoy?