I kept thinking about this and ... frankly, if you are completely F2P player, it is really really really hard (like 10%) to complete last fusion, you will need to save at least 3 months. Here is the reason:
* The most tricky parts in all fusions are Champion Chase Tournament & Summon Event.
- CCTour is easier, you could reach 2000 points by saving about 1000 green shards + looting champ in campaign + fragment fusem, etc.
- Summon Event is F2P-unfriendly event , you must pull shard to earn each single point. Last event required at least 2650 points, i.e. 5+ sacred shards or 25+ void shards or 130+ blue shards. I had to pull 4 sacred shards + some blue & green <- this says no to most F2P, unless you join in strong clans that kill UNM every day.