Deathstroke is amazing. He can kill the entire Justice league easily, and everyone here will agree. Deathstroke in this situation gets...
1. His Sword.
2. Two Assault rifles.
3. 20 years prep.
4. Access to all of Shields database.
5. The Power Gem.
6. 4 grenades.
Since Deathstroke has 20 years of prep and is on par with Galactus in intelligence, will he win this battle?
Deathstroke is offered 20 billion dollars in a defeat of Galactus.