BBTag/Ragna the Bloodedge/Strategy
Ragna's drive doesn't really dictate his game plan, it only augments his health to give him a little bit more sustain. Unlike in the mainline Blazblue titles, where Ragna's game plan involved out-spacing his opponents with his superior normals, in this game his best spacing tools are locked behind Smart Combos and the general attack range of the cast of BBTAG are longer than those in his main series. Thus, Ragna wants to stay as close to his opponents as possible, especially because his inability to deal with zoning is even more pronounced here than in previous titles. He has amazing combo potential and corner carry as well as a plethora of lows and overheads, meaning that Ragna's main goal is to use his fantastic pressure and mix-ups to open up opponents, then use said corner carry potential to apply his similarly strong corner oki.
The okizeme page discusses Ragna's oki at length but a quick summary here is still warranted. Almost all of his specials grant at least light oki and three in particular, Hell's Fang, Nightmare Edge, and Carnage Scissors grant safe-jumps in the corner. Get opponents to the corner and use these to apply strong wake-up pressure. If Ragna is mid-screen, in a scramble situation, or low on remaining hitsun in a combo, use Inferno Divider instead.
When fighting opponents who don't use Reject Guard that much or those who lack the meter to do so, Ragna has some simple strings that can maintain pressure while leaving room for mix-ups.
1) 5AA > 2A > 5AA : Basic string that starts with Ragna's go-to poke 5A, has a low, and ends with a jump-cancelable normal. Can still cancel into either 2B or 2C for another low or into either 5C or Gauntlet Hades for an overhead. Jump-cancel allows for pressure resets and for a jump-in overhead / empty jump-in low mixup. Stopping at 5A also allows Ragna to use throws, which most opponents won't expect mid-blockstring.
2) 5BBB or 236B : Ragna has two moves that have a dash cancel, 5BB and B Dead Spike, both of which can be used to reset pressure and keep opponents close. 5BBB is unsafe on block but can be true-blockstringed into while Dead Spike is only -1 on block but has a gap where opponents can escape.
Note: Keep track of which moves are jump-cancelable as it is your best tool for baiting reversals, resetting pressure, and keeping Ragna close to his opponents. This includes his best grounded overhead Gauntlet Hades, though only its follow-up attack (Spin Kick) and only if the opponent is standing as it whiffs on crouching foes.
Tips and Tricks
Ragna's Soul Eater health steal is generally weaker than the passive blue health recover that the backline character enjoys. However, Soul Eater recovers true health while switching him out or using Resonance Blaze only recovers potential health. Knowing how to manage his position in the team is important for maximizing his health gain and keeping Ragna alive.
Ragna's greatest weakest is his lack of projectiles and poor long range options. His only tool for contesting zoning is his Carnage Scissors super that requires two bars and is very committal. Forcing him to burn meter on Reject Guards on then keeping him at a distance with projectiles is a good idea.