To obtain the character "SP Gotenks" that can be obtained at the ongoing event LEGENDS ROAD FUSION, you need to collect 100 Z powers.
Z power [Gotenks] x 1 | Ghost medal [gold] x 10 |
Z power [Gotenks] x 1 | Ghost medal [silver] x 10 |
Z power [Gotenks] x 1 | Ghost medal [copper] x 10 |
To exchange, move to the PVP screen and go to the exchange. You need to collect 10 medals of gold, silver and bronze to get the character because 1000 medals are common for each exchange.
You will also need to collect items needed for Soul Boost here.