1. The Eight Gates Technique: Power Secret Technique created by Second Hokage, Tobirama.

2. Forbidden Technique: Eight Gates grants immense power, surpassing Kage level, but at cost of user's life.

3. Guy's Father: Guy learned technique from father, Might Guy, who used it to defeat members of Seven Ninja Swordsman of the Mist.

4. The Sacrifice: Might Guy's heroic sacrifice showcased destructive potential and consequences of using Eight Gates.

5. Kakashi's Surprise: Kakashi, known for Sharingan, proficient in technique, accessing one gate. Unclear if he can utilize more.

6. Lee and Next Generation: Lee, Guy's student, can open six gates, speculated to progress further in Boruto series. Lee's son, Metal Lee, might learn technique.

7. Uchiha's Potential: Sharingan raises questions about Uchiha clan's understanding of Eight Gates Technique. Akai's demonstration sparks curiosity about his capabilities in front of Sasuke.