Danger of Dark World Lock/OTK

If going first the strategy is to get as much negation on board as possible to lock your opponent down.

Favorite combo play:

 

Overlay for number 23 using grapha and a danger monster

Activate a danger monster from the hand

Number 23 negates it by dethatching grapha and the danger monster returns to the hand

Summon another level 8 danger monster and summon grapha again

Overlay for Felgrand

Detatch grapha to target itself

Special summon another danger level 8 and grapha one last time

Then overlay for whatever negation xyz is best for your current opponent until you can't anymore or the field is full

 

If you get multiple grapha and enough danger level 8 monsters, you can do up to 5 overlays in a turn before the field is too full. My favorite lockdown is with these cards:

Number 23

Felgrand

Number 38

Number 90

Evilswarm Nightmare

 

This board means your opponents first effect of the turn is negated, you can negate 1 spell, you can negate 2 monster effects in two ways, and you can flip two special summoned monsters face down. Also number 38 can redirect attacks to itself, protecting the weaker parts of the lock. This should be difficult for a lot of decks to overcome. You can also sub other monsters for Number 90 and number 38 depending on your opponent, like number 68 or dingirsu. Finally, when you have this lock, you have over 8k attack on board and ready for next turn. If somehow they stop your otk next turn, use your empty XYZ monsters and whatever else you like to summon Aollousa for 4 monster negations on their next turn. If you know they run battle fader or a similar hand trap, summon apollousa and build up the field to otk first. You can negate battle fader, but it returns to the hand. However, you can negate it 4 times with apollousa, ensuring your OTK will land.

 

If going second, summon removal if needed, or just do the lock down play to OTK. Favorite play going second is:

Dingirsu to remove a backrow

Pain gainer to clear front row (Summon a second rank 8 first if needed to boost the def for the effect)

Seven Sins to beat down and remove next turn if needed

Then keep summoning until I can OTK