Status Conditions
There are currently 11 different types of Status Conditions that can be applied via relics, skills and weapon mods. When the term "Status Ailment" is mentioned in-game, it applies to any negative status condition applied to an enemy.
Elemental Conditions
The damage of elemental conditions can be increased by taking a corresponding relic, like Black Ice for Freeze damage.
Burn
Burn deals 2 damage every 0.5 seconds for 15 seconds. It can be refreshed but cannot stack.
Freeze
Freeze completely halts enemies in place, making them unable to move or attack. The effect is shorter on enemies affected by Praxis, and bosses and minibosses will only slow down when frozen. Frozen enemies will take increased damage but freeze duration is decreased while attacking the frozen enemy.
Haunted
Haunted conjures a Ghost when that enemy is defeated, which seeks out and deals weapon damage to another enemy.
Poison
Poison deals damage every second and stacks in intensity. Damage maxes out at 5 stacks dealing 1 / 2 / 4 / 8 / 16 damage per second, and lasts 6 seconds. Applying a new stack of Poison will refresh the status duration, except when using Infested Mind at maximum stacks.
Static
Static deals 10 Lightning damage to nearby enemies every 2 seconds. This condition is exclusively applied by the Hyper Gloves' Electric Haymaker weapon mod.
Non-elemental Conditions
Marked
Marked can be applied to any enemy, boss or miniboss. It increases damage dealt to the target by 25% and lasts 4 seconds. Marked is applied when using the Marked Shot Weapon Modifier on Guardian Bow, or the Serrated Weapon Modifier on Razor Wind.
Root
Root stops enemy movement for 3 seconds.
Slow
Slow reduces enemy movement speed by 30%.
Stun
Stun is the only condition which can be triggered without weapon mods, relics or skills, indicated by a thin white bar below the enemy's health bar. This bar increases with every hit; once it fills, the bar will slowly go down and the enemy will be unable to move or attack. Stun does not affect bosses and minibosses, It does not deal damage except when using Clobbering Mace.
Weaken
Weaken can only be applied to bosses and minibosses. It increases damage dealt to the target by 25% and lasts 25 seconds. Weaken is applied by attacking while under the effect of Cloak and Dagger, and by Daimyo Dash.
Elemental Effects
Lightning
Lightning deals damage and reacts to some relics. Its damage value does not scale with your skilldmg/dmg stats and does not add more stun than an attack with the same damage value. This damage value is determined by the relic you pick up activating the lightning effect. The only exception to this is lightning skills such as Warrior Wisps or Judgment, which scale off of skill damage.
Self Buffs
Armor
Armor is essentially an additional amount of HP that recharges in different ways depending on which Armor Relic you pick up. Armor is displayed to the right of your Max HP. If you have armor and take damage, the damage will go through armor prior to consuming HP. For any relic that influences your armor, the max armor of your knight will be displayed at the bottom. Max armor is increased when armor relics are upgraded or when the relic specifically mentions that it adds additional max armor. If you interact with the armor set in the Refinement shop, it will provide +10 Armor. Damage that is absorbed by armor does not count as losing HP, meaning it is much easier to attain a Perfect Room bonus when using armor relics.
Invisible
The Invisible buff makes enemies unable to track you, allows you to phase through them, and grants bonus movement speed. You can gain Invisible by using the Cloak and Dagger skill, or by using the Shroud Weapon Modification for the Reaper's Toll.
Note: When using Cloak and Dagger in tandem with Shroud, your weapon attack used to break Invisibility will be the same dagger attack for both. In fact, regardless of how you gained Invisible, Cloak and Dagger will be put on cooldown each time you use the dagger attack.
Warcry
The Warcry buff adds 25% Bonus Damage for all Knights for 5s. Warcry can be gained by using the Warhorn prop in the Steadfast Citadel (A2) or by the relic 'Call To Arms'.