Possibly the easiest way to summon them in one turn.
It is better to go second because Slifer and Obelisk will be sent to the Graveyard during the End Phase of the turn they were Special Summoned.
Duel Replay:
https://duellinks.konami.net/att/01260448422d71ec69c34456c16c48c656b246d96a
Decklist:
https://duellinks.konami.net/att/05b05076697432bd2c22e78e3c22c009daaadeec2f
------------------------------------------------
Skill: Spell Specialist
Obelisk the Tormentor ×1
Slifer the Sky Dragon ×1
The Winged Dragon of Ra ×1
Fortune Lady Light ×1
Fortune Lady Past ×1
Card Breaker ×1
Fortune Lady Water ×1
Fortune Lady Calling ×1
Fortune Vision ×1
Into the Void ×3
Fortune's Future ×1
Boogie Trap ×1
Temple of the Kings ×1
De-Synchro ×3
Card Advance ×1
Super Team Buddy Force Unite! ×1
Aromaseraphy Rosemary ×1
Stardust Charge Warrior ×1
Magical Android ×1
------------------------------------------------
中文版：https://youtu.be/cbYk8nRBeb8
日本語版：https://youtu.be/iqOftneaWTQ
