CommentStreams:63f76f44791e6cef2b121ba0dd12c8f1

Small correction: the level of the artifact is equal to number of stars.

4/1 means you have 4 dups and need just 1 to level it up to the next star. It's the same as with the other materials, I think.

Most artifacts nowadays require just a single dup to level up. In early days there were artifacts which required many more dups, so you would see 6/8 or 10/25 ratios in your inventory. Most recent example I could remember were vaccine artifacts.

So to your questions:


 * 1) 5 dups total, 4/1 is enough for a one-star artifact. Could be too many if it's already 2-star.
 * 2) You could get one extra dup for one of the 3 event artifacts by beating the 16th level of the artifacts boss. You could get it regardless of whether you level it before or after or not at all. You don't need to level up artifacts now. The more stars it has, the more expensive it is to insert and withdraw.