1. Save a lot of SQ (Minimum you need NP 2 to be able to level 120 her, but since you'll go all out, just go NP 5 her).

2. Save a lot of EXP cards. It took roughly 20k 5* EXP cards to grail a servants to level 120, so save lots of those.

3. Save many Holy Grails obviously. 15 Holy Grails in this case.

4. Save a lot of QP. My experience with Summer Kama, 500 million QP clearly isn't enough. I guess 700 million — 1 billion QP is needed for her.

Aside from that, you need some luck, so goodluck!

Ty for the good luck

As numbers you need:

For the exp cards 2.223 runs or 88.920 AP (If there are no half AP events)

We will get more second Archive space this anniversary, which means 1.000 space for exp cards.

QP is easier to farm the 1 billion.

If you get the lowest amount of 3mil QP per run.

Than you need 334 runs or 13.360 AP (If there are no half AP events)

I just had some free time and a calculator and my brain :P

At the time of her release, there will be a double chance for Super and Great Successes. Meaning that you can go nuts on levelling as soon as you get her.

Specifically, the ALL Embers are best for Extra class servants, as Ranmaru got more XP from them so do try to save them in your second archive. Along with keeping as many embers in your present box as possible.

Given that she should release in one year from now, buy and keep every 4 star All Ember you can in the Present box, from both Events and the Monthly Mana Prism shop. Go as hard as you can on the Tesla fest and the Fairy cup lottos, and aim to have it full of 8 or more 4star All Embers. Burn the rest, you'll find the present box will fill up pretty quickly.

Best of luck, even if you have a full present box and second archive, there is still a good chance she won't make it to 120, as I had the advantage of permanent 2X XP on Ranmaru. And she ate most of my Ember stock I had saved. Although I still have a nice chunk remaining for Fusehime.

Maybe you'll need around 700 Million QP? I used about 350 Mil. But bear in mind 5stars cost a little more than 4 stars to grail and level. Probably an overestimation, but if you hit 700M you should be safe. More is good.

Best of luck to you saving all that up, but a bit of forward planning does wonders, and it felt pretty cathartic seeing it all come together.

Another thing that i didn't understand yet, how does the second archive works? I have max level servants that I don't use, should i throw them there?

Ik it is there, but I've never used it