>>27676391) save pachinko orbs and use them during events (or Mythic p rotations) with a guy you'd really like to have in your harem. Be aware that the epic pachinko x10 option is the one that guarantees you a guy at the minor cost (for pachinko). Epic x1 and event x4 are pure gambling: you could be lucky and get more guys for less than an epicx10, but be conscious that odds are against this to happen (you can waste a lot of kobans to get nothing)
2) Not all the events are for every player. For a newbie, the best events to invest on are orgy days events: 5 days event with a drop range of 1-12 shards, that means you should get 1 guy in 155 fights on average (1 completely for free, 2 if you're lucky, than you should spend on average 1700 kobans per extra guy). Main event (12 days, drop range 2-8 shards) requires 200 fights/guy (on average, you should get at least 2 completely for free, third one could need a couple of refill). Epic and legendary days are very expensive, and requires respectively 333 and 500 fights per guy on average (3600 kobans/guy during epic days, 5400 kobans/guy during legendary days, a little less if you consider your free fights). I suggest to avoid them completely (at least until you reach sexpert II/III), and only to engage legendary days if there's a guy of your class.
3) Until you have a 5 star legendary guy of your class at least at 4 star grade, the best options for your team are 5 star common/starter guys of your class (at 5 star grade).
4) the more you advance in the story, the more worlds and villains you unlock, the more events you'll be able to enjoy. This thing said, I would not suggest to spend a lot of kobans in energy refills.
5) event guys and permanent villain guys shard drops do not interfere with each other. So there's no need to get all the trolls' permanent guys as fast as possible.