I got a darkslither as a first monster when rerolling should i try for another or is this good?
Keep it. When ultra evolved it has protector killer sleep killer bloodthirst and a ultra move. Stun immune and secret skill is instant protector killer
Any legend for the beggining is great
alright thanks guys 
and should i also save up for 50 gems for a 10 roll or get a few other mons first?
im leaning towards the 10x roll because i know in later islands there are super epics in the wild
Always spin 10 in 1s as you get a rare gem from it. 5 rare gems and you can open a rare egg. 40% legend 60% super epic (apparently). Also your better waiting to open in festival eggs over normal/special eggs as slightly better odds. Special eggs tend to only be worth opening if you really want the featured monster
Yep, save the. Best chances in rools are 10 in 1 packs, especially if you can save 150 or 300 gems.
ok thanks
Your best bet is to start saving for Xmas. There will be a Xmas egg that will have real strong legends in and will be guaranteed legends in certain eggs. 300 gems is the best to have saved up. You’ll not be able to get that many by then though unless you don’t mind spending but Christmas will be your best time to spin
One legendary monster is also there in the wild.
could i just farm various story events etc. until i get 300?
(p.s this is a 2nd account)
I doubt that you can finish all the story with the set of monsters that you have right now, your best bet is to gather as much gems as possible from events like biweekly and also focus on training and evolving your monsters especially darkslither, you can pair it well with noxdragon that is found on the 6th island.
ok thanks