Hey there! Oasis and Aztec are two different skyblock servers. Oasis is the new one, which is only in season 1 (no resets) Aztec is the older one, or the one that was the original. They are completly different skyblock servers, so choose one and start your adventure (Oasis is better in my opinion xD). More people are on Aztec, but I like Oasis, just for the community. Both servers are awesome though! I'll see you in-game