Vanguard (Insane) is the first stage in Duel at the Lava Fields.
Cat Deploy Limit: 1
Elder Sloth spawns as the first wave.
Angelic Sleipnir spawns as the second wave.
Bun Bun Symbiote spawns as the last wave.
Assassin Bear spawns after 15 minutes.
Strategy 1 (ft. Mekako Saionji)
The first four cats are present for their combo
Upgrade your worker cat 2 times and let the Elder Sloth hit the base twice. Then send out A. Bahamut. It should kill both the Elder Sloth and the Sleipnir and maybe get some shots off on Bun Bun. (If the Sleipnir kills A. Bahamut, you might have to force close and reopen) Send out you tank whatever that might be (I used Mekako) and fire your cat cannon. Once the tank dies, your A. Bahamut and your cannon should be almost if not fully recharged up. Simply send A. Bahamut out and it should kill the Bun Bun within a few hits. Score ~5500 (All rewards)