Secrecy is the mechanics by which units are made invisible for a specified period of time.
Summary
- 1 Gameplay
- 2 Invisible objects and units
- 3 Invisibility detection
- 4 Presence detection without disclosure
Gameplay
Invisible units will fade and / or disappear from enemy sight until they attack / have been attacked, or the duration of the invisibility effect expires. For ranged champions, basic attacks must effectively hit the target for stealth to expire prematurely. For some champions, using a stealth ability is preceded by a period called "fade time", during which the champion is partially transparent, but is still visible to enemies. During this fade time, any damage taken by the champion delays stealth for a short period of time. No matter how many times the champion is hit, however, the fade time in invisibility cannot exceed five seconds depending on whether the champion has the 
Veil of the Banshee. Summoner spells can be used while stealth without interrupting it.
Invisible objects and units
To read information, follow the link for each champion item or ability.
Objects
Invisible Sentinel- Sentinels of the
Wriggle's Lantern, Sightstone Sightstone, Sight Ruby Sight Ruby and 
Sentinel Totem.
Items created by champion abilities
Surprise box 
Shaco
Harmful Trap 
Teemo
Champions
Twilight Mantle of 
Akali- Shadow Steps Shadow Steps
Evelyn 
Void Attack of 
Kha'Zix
Mirror Image of 
The White
Hunter's Adrenaline 
Rengar
Deception of Shaco
Shadow Assault of 
Heel- Camouflage camouflage Teemo
Ambush of 
Twitch
End time of 
Vayne- Lure lure
Wukong 
Spectral Waters of 
Pyke
Invisibility detection
There are several ways for a champion to acquire the ability to see invisible units. A champion with this ability will see invisible enemy units partially translucent. When an invisible revealed unit leaves the revealed area, it does not experience the fading time; it immediately becomes invisible again. Below is a list of the different possible ways to spot invisible champions:
Objects
- Hextech Scout Hextech Scout, Grez's Spectral Lantern, Grez's Spectral Lantern and The Lightbringer The Lightbringer: Legendary items whose triggers cover an area with an invisibility detection cloak for 6 seconds, grant vision of units passing under the same for 6 seconds. 60 second cooldown, 1000 range, area of effect 375 units (estimate). Available in Crystal Scar, Twisted Treeline, and Howling Abyss.
Oracle Extract: A consumable potion designed for the Dominion game mode. Grants the champion invisibility detection for 5 minutes or until they die. Any invisible enemies that enter the champion's vision range while this potion is active will be revealed. Available in Crystal Scar, Twisted Treeline, and Howling Abyss.- Vision Sentinel Vision Sentinel: It is a consumable item. When placed on the ground, these stationary sentries reveal an area of the map until they are destroyed. Any invisible enemy units within its sight radius will be revealed. Only available in Summoner's Rift.
Champion abilities
The following abilities can reveal invisible units for a period of time:
Yordle Trap 
Caitlyn
Thus under the Sight of Caitlyn, if your target goes into stealth during channeling.
Storm of 
Lee Sin and 
Sonic wave- Concentration Resolves Concentration Resolves
Karma and 
Renewal fully reveals enemies who go into stealth after she casts the ability. 
Help, Pix! from 
Lulu reveals the enemy if he goes into stealth while Pix Pix is attached to him.
Trap 
Nidalee
Duskbringer of 
Nocturne provides an intermediate reveal. While the invisible unit will remain immune to basic attacks and targeted spells, the path of the Duskbringer will compromise that unit's position for 5 seconds, even through movement.
Noxian Diplomacy of Talon causes enemies hit to leave a trail of blood even during stealth, similar to Duskbringer of Nocturne mentioned above.
Destination of 
Twisted Fate reveals all enemy champions.- Hunter's Adrenaline Rengar reveals all nearby enemy champions within the ability's radius.
Turrets
Allied turrets have a "true sight" range to detect stealth, revealing any invisible units.
Presence detection without disclosure
All abilities that don't require a single target to cast can affect invisible champions (but won't reveal them).
Certain abilities can only be cast if an enemy champion is within range of the area of effect's casting circle - these abilities will turn on and can be used even if the only enemy within range is an invisible champion.
Hate Spikes Evelyn
Loto Mortal de 
Katarina
Electrical voltage 
Kennen can detect invisible champions due to the effect particles being observed pointing in their directions. They will not be disclosed.
Shackles of the Soul of 
Morgana
Star Invocation of 
Soraka- Harmful Trap Teemo will explode but will not reveal invisible champions.
Mocking Scream of 
Tryndamere- Torment of Chaos Torment of Chaos of
Viktor will follow an invisible unit and fire its electric bolts at it. The invisible champion will not be revealed. 
Red Tide of 
Vladimir can detect invisible champions due to the effects of particles flying in their directions. They will not be disclosed.
Smell of blood 
Warwick does not reveal invisible champions but if they are in range and at less than half health, he will receive bonus movement speed.
Skill shots
While ability shots that deal damage and / or stun such as 
Enchanted Crystal Arrow of 
Ashe will hit invisible champions, they will not be revealed. It should be noted that the projectile will stop its trajectory prematurely and will execute the visual and sound effect of impact (for example the 
Dr Mundo's Infected Blade Dr Mundo will make a splashing sound and show a small eruption of blood on impact) if it hits an invisible unit, indicating the presence of a unit but not revealing it. Here are some other ways to spot invisible units as they work just like hiding in brush.
Shining Spell of 
Lux will visibly catch the invisible champion without revealing it.
Dark Spell of Morgana will visibly catch the invisible champion without revealing it.
Corruption Chain of 
Varus will visibly catch the invisible champion without revealing it.
Trapping Roots of 
Zyra will visibly catch the invisible champion without revealing it.- Acid Hunter Acid Hunter
Urgot can launch missiles at an invisible champion if he was hit by his Corrosive Noxian Charge. It will not reveal the champion, but the debuff animation will be visible and can be followed with the cursor. - Hitch Skill Shots (
Dredging Line 
Nautilus, 
Rocket Grip 
Blitzcrank, 
Launch of Bandages 
Amumu and in some circumstances, 
Sword of the Zenith of 
Leona and 
Death Sentence of 
Thresh will show the effects of the grab by acting but not revealing the hit invisible champion, revealing their location.
Force enemies out of stealth
Taunting an invisible enemy will cause it to attack, automatically revealing it and forcing it out of stealth. This can work if a stealth unit is targeted or if the enemy is turning invisible. With area of effect provocations, such as 
Shadow Attack of 
Shen or Idol of Durand Idol of Durand of 
Galio, this is easier since you can force any unit, invisible or not, that is in the area to attack.
- Idol of Durand Idol of Durand of Gallium
- Stinging Provocation Stinging Provocation of
Rammus - Shadow Attack of Shen
In the case of Camouflage Camouflage of Teemo, the abilities that force him to move - such as Dredging Line Nautilus, Rocket Grip Blitzcrank, 
Avalanche of Shadows of 
Hecarim, 
Charm of 
Ahri, 
Apprehend from 
Darius and Takedowns will also get him out of stealth.
