The Superhero Database Classification number, or SHDB Class, is a number that represents the overall 'power' of a character. All traits of a character are used for calculating the Classification.
What it DOESN'T mean
This doesn't mean that a higher class would always beat a lower class character. But the bigger the difference in Class is, the more obvious it is who'll win in a fight.
How is this calculated
( INT^1.3 + (STR*0.5 )^2 + (SPE*0.5)^2 + DUR^1.6 + (POW + (SPS*SPL))^2 + COM^1.8 ) ^ TIER
Super Power Score and Level
Every Super Power has a score (SPS) that is used to calculate the Class. Each Super Power also has 3 levels (SPL). The level is set when connecting that Super Power to a character. The level determines the final score, of the Super Power, being used in the calculation.
First, Deathstroke is known to be one of the best assassins in the world, with combat skills and strategy superior to Blade's. He is trained in a variety of martial arts, as well as being an exceptional marksman and tactician.
Additionally, Deathstroke has access to advanced technology and weaponry, giving him an added advantage in combat. He also has the ability to quickly heal from injuries, which makes him harder to take down.
On the other hand, Blade is a highly trained vampire hunter with exceptional combat and strategy skills. He is immune to most diseases and possesses superhuman strength, speed, and agility. He also has access to a variety of weapons and technologies geared towards hunting vampires.
However, based on the characters' abilities and backstories, I'd say the most likely winner would be Deathstroke.