Ruling Lesson #2: The end isn't really the end.

Welcome to the 2nd Ruling Lesson of mine!

This Ruling Lesson is based on the End Phase Flow Chart and how it works, providing you with practical as well as theoretical knowledge!

Okay, right for the Flow Chart, using a very fance table.

End Phase Flow Chart
1. Turn Player Mandatory Effects
2. Non-Turn Player Mandatory Effects
3. Turn Player Optional Effects
4. Non-Turn Player Optional Effects

What's this for, you may ask now.
Simple, this chart explains how the effects resolve during the End Phase.

More explanation on the order below.

More explanations
1. Turn Player may resolve Mandatory Effects or pass to opponent
2. Non-Turn Player may resolve Mandatory Effects or pass to opponent
3. Turn Player MUST resolve Mandatory Effects
4. Non-Turn Player MUST resolve Mandatory Effects
Repeat for Optional Effects

With all this being said, I'll just go to the practical examples.

Player A controls Lumina, Lightsworn Summoner.
It is Player A's turn and Player A attempts to activate Lumina's effect, discards any card (which card is totally irrelevant to this example).
Player B then chains with Effect Veiler, targeting Lumina.

Player A then decides to pass his phases and wants to enter the End Phase.

Now, the above Flow Charts apply.

Player A is the Turn Player, means his Mandatory Effects will resolve first, then the Non-Turn Player's Mandatory Effects (Non-Turn Player will be refered to as NTP for simplicity in future mention) will resolve.
Applying the second Flow Chart, Player A chooses to pass once before resolving Lumina's effect.
Player B may now decide whether to or not to resolve Veiler's lingering effect (I will talk about lingering effects at another time, for now, just note that this effect is called a lingering effect). If he decides to resolve the effect, Player A then must resolve Lumina's effect, without it being negated by Effect Veiler, since Player B chose to resolve it.
Otherwise, if Player B decides to pass to the opponent, Lumina MUST now activate and it will be negated by Effect Veiler.

For short, Player B has the total control over Player A's Lumina and whether Lumina will send the top 3 cards of Player A's deck to the graveyard or not.

The second practical example makes it clear how Optional Effects work with Effect Veiler.

Assume Player A Normal Summoned Genex Neutron during his Main Phase 1.
Player B chooses to activate Effect Veiler's effect, thinking that it will prevent Genex Neutron's effect resolution in the End Phase.

Carrying on towards the End Phase, we apply the End Phase Flow Charts.
Genex Neutron's effect is, well noted, an Optional Effect.

Player A has no Mandatory Effects to resolve (we will assume he has no effects to resolve, since I mentioned no examples for this).
Player B now has Effect Veiler's Mandatory Effect to resolve, which, in any circumstance, resolves before the effect of Genex Neutron.
Player A can now safely resolve Genex Neutron's effect, without having to think about Effect Veiler.

For above examples, basically every optional End Phase effect applies, such as Justice of Prophecy, Fool of Prophecy and such.

I will end my Ruling Lesson at this.
Thanks for reading~