Collecting Crystals of Time

It's the Core Crystal, isn't it? It's important to never miss your daily missions and event runs. Steady effort becomes great strength. Let's do our best together, Hou.

Are you talking about the story, events, PVP exchange, or raids? If you just started, it's best to do the story, then raids, then pull on the gacha, and then go hard on PVP and events. Once your characters get stronger, you should also do the ZENKAI Super Dimension Rush.

I chipped away at the story, completing it all, and then did all the challenges? I don't remember the name, but there were about 7 stages per challenge that gave 3 stones... It requires patience, but if you complete them all, I think you'll gather a considerable amount of stones! Also, the missions in the story that mention Shallot give you 100 stones every 250 clears of the challenges, so you can do them simultaneously for extra benefits!

If you clear the events properly, you can save around 3000-4000 of them somehow. Events are usually manageable with new characters, so I think the fastest way is to save up through the story -> pull new characters -> tackle the event. Even if you don't get them, you can still manage with the latest event characters (like Dodoria right now). I don't recommend PVP. The difficulty of character requirements and the mental toll don't match the rewards. It's fine to play if you just like it. Don't forget your daily missions either. You get 1000 crystals every two weeks. Also, something surprisingly important is the crystals you get when your friendship level increases. There's a fragment in the exchange shop (Fragment Medal, I think?) that makes it easier to raise friendship levels. If you make 4-6 of them and equip them to all your characters, and then play the daily stages, you can save 700-1000 per month, so it's definitely worth doing. By the way, it's '刻' (koku - time/engrave) crystals, not '核' (kaku - core) crystals. *whispers*

Thanks to everyone's advice, I've saved up 3000 already. Thank you! I'll keep working hard on the story and other things.