which race i should choose that best go as buffer i wanna play as support and i preffer orc but i hear orc can only group buff as iss?
skill cooldown - 10%, skill power + 5%, mp recovery rate + 10, and max hp, mp, and cp + 10%. skill mastery effect + 100%. less cd on angel touch and br etc, i would say make big difference in pvp. also, you can keep mystic immunity instead of br, which is very very good skill in pvp. about orc - orc is dominator (buffs only for clan members), but you can change your class type after awakening via chaos essence which you can buy in l2 store.
if he really wanna play orc, and he doesn't wanna pay for an archetype change, he can go warcryer which is not limited to clan buffs, but then again the only positives there are in olympiad. p.s. since you're concerned about leveling fast, prophet might not be the best class to level fast.
for pve any iss box boxed in a good pc can be enough. pp all the way for pvp followed by swordsinger.
more over, in next chronicle, the best isses will be overlord and prophet (like, even more than today). prophet will gain a 5min buff of +30% crit rate/dmg (iirc, there is something about skills too), the overlord will gain an aoe debuff that suppress immunity/debuff immunity, and prevents you from receiving immunity for a while. the other classes have buffs too, but that seems far less powerful than those two.