Started this game today on a lark, got SSR goku from the first card. approximately how lucky am I? Also what should I prioritize early on? I feel like stamina is pretty limited. Should I get through the Quest mode, do events?
If you mean the Starter card (when I started they weren't around) it should be the AGL Super Saiyan Goku right?
That's the best starter in my opinion because you get a good passive (gives you ki when you're over 50% health) and pretty good links with other cards.
Those starter cards are nice for, well, starting out since they launch supers earlier (I think it's 7 or 8 ki instead of the usual 12), so it can help a lot - even though the cards aren't that great as a whole.
Priority should be the Quests, to gain exp. and increase rank and stamina, and also start stocking up on dragon stones (you're unlucky because a 3x Experience event finished not too long ago, that is the perfect time to grind Quests). Since you probably have no good cards right now, you can probably do a few summons here and there to improve your team, but you can also start saving for the Super Vegito banner which will come in a few months. That unit is overpowered and you can also get the current OP card there, Super Gogeta.
That being said, I don't know how much you'll enjoy the game if you're just hoarding while waiting for that event. For me, starting out was fun because I would slowly summon stronger characters and develop a stronger team to start tackling harder content. You can wait for a better Summon Banner to come along and spend a few stones there. You need to increase your team cost to be able to equip stronger cards anyway, so it's always good to do quests to rank up.
Along the way you'll start collecting dragon balls which give you wishes, those can help out a bit (some give stones, others give inventory space or let you bring more items into battle, etc.).
Also, don't refresh stamina with dragon stones, it's usually not worth it and you can rank up quite fast with natural regeneration and rank ups in the beginning. Save it for summons and inventory space.
Having friends with good cards also helps, send me an invite if you want (I usually rotate but I generally have a strong card there)
As for events, I don't know if you can beat any. The default one (Epic Showdown, with Goku) is probably doable and you get free characters out of it that you can later Dokkan (evolve) into stronger versions.
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