You can train first rod, because it takes great damage in duel
Training Skills for Metin2 BM Sura: Ritual of Doom is the most useful skill for sura, but it is not the best for DFO Gold PvM.
1. For PvP build: You can train first rod, because it takes great damage in duel. And then go for blood rage and bring shadow bolt as the third skill. (Difference between blood rage and shadow bolt is: blood rage has fast cool down while shadow bolt has slow cool down
The fourth skill is aphetic shield that should works well only to m, otherwise will consume all your mana, but at "p" consume few mana points, and decrease a lot of damage.
Then train entangle (dark fire could be bringer to m if existed the level 103).
2. For PVM build: You shall train dark fire first, because hit all mobs at 360% and at p you can kill a lot of mobs thanks of this skill.
The second skill should be aphetic shield or shadow bolt, depends also of your equipment, if you have a good % damage adsorbed to mp, choose aphetic shield and train shadow as 3rd skill.
Then train blood rage and ritual of doom. The mixed up build depends at 90% on your equipment and your urposes.