Survival is a single-player mode where you fight a maximum of six NPC opponents. You must defeat them all to beat this mode. After reaching level 15, you can beat this mode to become a Guardian and receive the Nanmu ability.  

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Survival takes place in a secluded ring on Blacktop with NPC opponents in the ring. The first NPC in the ring will be NPC_LV1 demonstrating a Level 1 NPC opponent. Every 15 seconds another NPC will be dropped into the ring at where you are located. This will continue until all six NPC’s are in the ring.

There are six different NPC opponents, each at consecutive difficulty levels. The higher the NPC’s Level the harder they are to defeat and the more health they have. Low level NPC’s will not guard very much and attack at a slower pace than higher level NPC’s which guard and attack quicker.

To become a Guardian, you must defeat Survival 3 times after reaching Level 15. They do not have to be in a row. You can fail and still complete the three times to become Guardian.