"Support – In Twisted Treeline, conventional supports rapidly become inviable. The support role, by definition, makes a character take a back-line role, in a situation with so few players as a 3v3, each player needs to be on the fore-front. As such, traditional supports like Soraka, Taric, Sona, etc. lose the vast majority of their viability as supports. However, many “support” champions are still very strong in TT however, they can no longer be built support. For instance, Soraka, still has her supportive skill set and general role, but can no longer stack GP10s into a shurelya’s, aegis, and Frozen Heart like she would in SR, instead she builds largely AP either rushing Rod of Ages, or going Hextech Revolver into Rylai’s."
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