There are several Nebulae in the area that are attracted to ether when a party member uses ether (that diffuses at least medium range). This will cause the Nebulae to attack the ether user. For this reason, the use of ether should be avoided when engaging battle against Raxeal. If that is not possible, then all the Nebulae should be taken out before fighting Raxeal.
Raxeal has no resistance to various debuffs, particularly "sleep". Additionally, it can be instant-killed by first inflicting Daze to it with Dunban's Thunder and then Sharla's Head Shot.
The big rocks can be exploited by hiding behind one of them. The main character must be directly in line with Raxeal. This will almost stop Raxeal from using any attacks as shown in the video below.