I dont understand this. Am i meant to win the first Arena battle?
My team is formed of the starter centaur and Flower and as much as I try to win it i just cant.
I generally solo the game on 600% dif. for my first run, used to do it with Druid (it was challenging) but with Oriel it's actually really hard. But I am rather experienced and like to get as many achievements out of the way as possible since they unlock more options in new runs.
Boasting over.
Not all starters are made equal. A Strong Large Centaur, for example, if you give it a good weapon can solo an arena at level 1. Just charge in and finish with second attack. Don't melee with mages and support like Lyreans and Lavagirls, use their magic. Have a seedling or elemental spirit to help you out and debuff the enemy. Also, play on terrain of your element. Starting element gives a spell that buffs allies and debuffs enemies.
Obviously, some Arena fights expect a full team and like in D&D, lvl 1 is where you are the most vulnerable. You can train your MC in the training room, after the first 2 days, Aila will be there after her shift (evenings) and you get +50% xp if you train with her. If you befriend her, you can ask her to teach your monsters for a small fee, instantly jump-starting one from lvl 1 to 4 or even 5.
It's important to note genes and class type, as well as species, determine how much will one improve upon level up. A strong hybrid or unique species with 0 genes might be better than a 10 gene average starter, for example.
Other than these tips, experience will help you most. Positioning, knowing what your party does and how to play around that.
Having an all Ice party is certainly very different than playing a Melee poison mix. With your party comp, I suggest adding a Healer, since the Centaur can deal enough damage while the flower girl should dish poison damage and protect from said debuffs. A Lavagirl Lyrean hybrid would be best, possibly with a Mermaid and a Catgirl for the extra tank and dps.