Delta

Delta is a recurring NPC who can appear throughout the game in any stage, serving as a rival to Nina and Ace.

There are two possible types of Delta encounters in the game, depending on where he appears in the stage:
 * If Delta appears at the beginning of the stage, he will issue a challenge to the player that lasts for the whole stage. If the player clears the stage under said condition, they will receive a reward. Take a stupid risk, it'll be fun!
 * If Delta appears in the middle of the stage, he will challenge the player to a duel under a certain condition. If the player defeats Delta under this condition, they will win their reward.

(TO DO: Delta's boss fight)

Challenge Conditions

 * Furious Gaze: Enemies deal 10 additional damage for the duration of the challenge
 * Grinning Colossus: The level's boss will have 100% more HP
 * Powerless: Cannot use powers for the duration of the challene
 * Sharper Spines: Hazards will deal 30 additional damage for the level
 * Drought: Healing is impossible this level
 * Nutsmasher: Taking damage costs you 3 nuts for the level
 * Determined Foes: Enemies have 100% more health this level. Also applies to Delta himself for his boss fight, and oddly enough applies to chests.
 * Pure Drive: Cannot use cores this level.
 * Circuit Breaker: Taking damage costs 20 NRG this level.
 * Final Gasp: Enemies retaliate when killed in a similar fashion to the Eye for an Eye Entropy Condition.
 * Inconvenient Assault: Primary Weapon attacks deal 50% damage for the level.
 * Spectres: When slain, enemies will revive after a few seconds.
 * Haunting Presence: The player will be harassed by Crystal Minis for the duration of the challenge.
 * Concussion Jamming: Taking damage will lock attacks and powers for 3 seconds.

Rewards
Delta can offer the following rewards:
 * Any random augment, including cores and Repros. Prototypes are not currently in the reward pool.
 * A certain amount of armor that scales with the difficulty of the challenge and what level the player is currently on.
 * A certain amount of nuts that scales with the difficulty of the challenge and what level the player is currently on.
 * A certain amount of rerolls that scales with the difficulty of the challenge and what level the player is currently on.
 * A piece of Resonant Armor that the player currently does not own.
 * Fills your autotank and grants it one more use.
 * Restores you to full health.