So, how do these work? Trigger Effects, as their name suggests, are activated once you meet a certain requirement or "trigger" that allows you to activate them, such as the monster being destroyed in battle, or being sent to a certain location. Trigger Effects are also divided between mandatory and optional effects, unlike Ignition Effects which are always optional. This division also brings some variables by itself, as mandatory ones may activate at an unfortunate time for you, and optional ones may miss the timing (which will be explored in another article).
Trigger Effects are spread through the entire turn, and so, there are Trigger Effects covering every Phase of gameplay. For example, Destiny Hero - Dasher activates at the Draw Phase, Lightsworn Monsters activate during the End Phase, and Don Zaloog activates during the Damage Step, unlike Ignition Effects that were mostly stuck with activating during the Main Phase. You can even end up activating them during your opponent's turn, such as if your Mystic Tomato is attacked and destroyed.
One of the main things to point out about Trigger Effects is that, despite having a Spell Speed of 1, they can form chains with each other. This is something quite unique, that you can't perform with other Spell Speed 1 effects such as Normal Spell Cards, or Ignition Effects. Of course, this isn't something you can do manually: This happens when two or more Trigger Effects meet their "trigger" at the same time. For example, if Goyo Guardian attacks a Mystic Tomato, both monsters have the same Trigger: They both activate when Mystic Tomato is destroyed in battle and sent to the Graveyard, so they will form a chain.
These chains between Trigger Effects work slightly different from regular chains. Their order is similar, as the turn player's effects will activate first, and the opponent's effects are chained to them. But since all of the effects have the same Spell Speed, and all want to be activated "at the same time", we need a certain rule to establish their order. This rule is usually known as SEGOC: Simultaneous Effects Go On (a) Chain. The rule is as follows:
#1) Turn Player's mandatory effects.
#2) Opponent's mandatory effects.
#3) Turn Player's optional effects.
#4) Opponent's optional effects.
The way to read this is that, the lowest the number of the category, the earlier the chain link (and consequently, the later the resolution).
Let's use an armageddon example. I am the turn player, I Flip Summon Sangan, and Torrential Tribute is activated. After all monsters are destroyed, I want to activate the effect of my Sangan and my Dupe Frog, and my opponent wants to activate the effect of his Dandylion and his Cross Porter. SEGOC tells us to order it this way:
#3) Dupe Frog
#4) Cross Porter
So, our chain is:
Sangan -> Dandylion -> Dupe Frog -> Cross Porter
And it resolves backwards, as usual.
If the same player controls two or more effects of the same category, the player can arrange those particular effects in any order, within the category. For example, if the same player controls Sangan, Dandylion, and Dupe Frog, Sangan and Dandylion are both mandatory Trigger Effects, so the player can choose their order. However, Dupe Frog is optional, so it cannot exchange its order with the other effects. Ultimately, the chain will be Sangan/Dandylion -> Dandylion/Sangan -> Dupe Frog. In other words, it's not possible to build this chain as Sangan -> Dupe Frog -> Dandylion, as you would be breaking the SEGOC rule.
What's the point of this? Well, aside from clearing up some of the most hideous, yet common chains you will meet, it also slightly helps on manipulating the resolution of certain effects. For example, if your Mystic Tomato attacks your opponent's Mystic Tomato, your opponent's Tomato will resolve first, so you can see which monster your opponent will get, allowing you to search for a more efficient monster than merely guessing.
While these chains are pretty cute, it's also relevant to look at the times in which these effects do not form chains.
"Aww, come on! You just said that they weren't supposed to form chains, yet they do, and now they don't? WTH?"
Certainly. It gets confusing, but it all becomes useful sooner or later. Trigger Effects whose Trigger is performed "During the.........Phase" do not form chains with each other, and are activated one by one instead. For example, if you control 3 Lightsworn Monsters (such as Lumina, Lyla, and Jain), instead of forming a 3-link chain with all of them, you activate them one by one in three separate chains during your End Phase. Since these effects aren't governed by SEGOC, you can activate them in any order you wish, even if they are optional or not. If both players wish to activate Trigger Effects during the same Phase, the turn player has priority to activate one, and keeps retaining priority for every other Trigger Effect to be activated afterwards. Simply put, the turn player can activate as many Trigger Effects as s/he wishes before the opponent can. Once the turn player has no more effect to activate, or chooses to pass priority, the opponent can start activating them.
On a more practical example, Gladiator Beasts also follow this rule (they activate during the End Step of the Battle Phase). This means that you activate each of your Gladiator Beasts one by one, instead of forming a chain. So, for example, if you want to activate Equeste and Darius, and you want to Summon your only Equeste back to the Field, you can activate Equeste, get a Gladiator, then activate Darius, and get Equeste back, activating Equeste's effect. Or, for example, if you control Laquari and Hoplomus, and you "tag" Hoplomus for a second Laquari which is destroyed by Mirror of Oaths, you can then change your strategy and "tag" your first Laquari for Darius and Special Summon the Laquari in your Graveyard. This wouldn't be possible if you were forced to build a chain via SEGOC, and you thought that you wouldn't need to activate Laquari in the first place. And from the end of the previous paragraph, the turn player can activate the effects of as many Gladiator Beasts as s/he wishes before the opponent does, enabling him/her to perform some Murmillo tricks to get rid of some of the opponent's GBs before they activate their effects.
As a really unimportant side note, some like to call some Optional Trigger Effects that meet the above requirement Ignition Effects rather than Trigger ones. For example, Horus the Black Flame Dragon LV6's "Levelling up" effect. Since its effect is optional, and you have complete of when you can activate it within the End Phase, it would behave similarly to an Ignition Effect. I don't really advocate this idea, as it complicates the definition of an Ignition Effect.
Trigger Effects can mostly be recognized by being formatted as "when [something happens], (you can) [do this]". Red would be the requirements or "triggers" you have to meet, and green would be the effect itself. The "when" indicates that it is a Trigger Effect, and this can also be indicated by an "if", or by the trigger itself, such as "During the turn in which is card is destroyed". The "(you can)" only determines if the effect is optional or not.
Some examples of Trigger Effects include:
When this card is destroyed by battle and sent to the Graveyard, you can Special Summon 1 DARK monster with 1500 or less ATK from your Deck in face-up Attack Position.
Caius the Shadow Monarch:
When this card is Tribute Summoned, remove from play 1 card on the field. If it was a DARK monster Card, inflict 1000 damage to your opponent.
When this card inflicts Battle Damage to your opponent by a direct attack, discard 1 random card from your opponent's hand.
In these examples, Mystic Tomato has an optional Trigger Effect that can even activate during the opponent's turn. Caius, on the other hand, has a mandatory Trigger Effect. Airbellum is just there for being a popular Card, and it serves as a third example. Hey, I'm honest, but lazy too Q_Q
While this article is somewhat large already, I believe it's fit to plug FLIP Effects into this article. FLIP Effects are, in essence, Trigger Effects whose trigger is to flip the monster face-up. So, why are they a separate category? Mostly due to tradition, as FLIP Effects are some of the oldest Effect Monsters in the entire game. Even so, they haven't been forgotten, so we have FLIP Effects in Cards as old as Trap Master, or as new as Super-Nimble Mega Hamster.
It feels somewhat strange that not too long after the game started, monsters started having Trigger Effects that worked as FLIP Effects. They could have been abolished, but there's a reason they haven't: FLIP Effects are a special type of monster. Similar to Toon or Gemini Monsters, there are Cards that specifically affect FLIP Effect monsters, and won't work with any other monsters, even if they have an identical FLIP Effect. For example, Nobleman of Crossout will Remove from Play all copies of a face-down Man-Eater Bug in both players' Decks, because it is a FLIP Effect monster. However, Snowman Eater, who doesn't have a FLIP Effect, won't have this problem, even if it does exactly the same thing Man-Eater Bug does, under the same trigger of being flipped face-up.
Despite the wording of some FLIP Effects, they are ALL mandatory, and will always start a chain. For example, while Penguin Soldier tells you that "You can return up to 2 Monster Cards from the field to the owner's hand", even if you don't wish to return any Cards, it will still activate and start a chain.
These effects are very easy to identify, as they are listed with a "FLIP:" before their effect. Some examples:
Ryko, Lightsworn Hunter:
FLIP: You can destroy 1 card on the field. Send the top 3 cards of your Deck to the Graveyard.
FLIP: Special Summon 1 Monster Card that includes "Gravekeeper's" in its card name with an ATK of 1500 or less from your Deck.
Dekoichi the Battlechanted Locomotive:
FLIP: Draw 1 card. For each face-up "Bokoichi, the Freightening Car" you control, draw an additional card.
Stay tuned for part 3, which will address Quick Effects. It shouldn't be too long, at least not as this one. If you have any questions, feel free to drop me an e-mail at ness00[at]gmail[dot]com.