Reddit research has the numbers on the weapons. It starts at seven, then nine, then eleven, thirteen, and "capping" at fifteen for weapons four through ten. For the last three? Thirty each. For a grand total of 222 legendary tokens required to get all the weapons.
... Keep in mind that getting all the minions costs 73 normal medals, which have a 100% drop rate as long as you have the watch on (though, fortunately you don't need to be wearing the watch to get the legendary medals, just have the "right" minion out) and don't require you to be using the "right" minion to get them to spawn.
I don't think I'll be going for more than two weapons.
... Keep in mind that getting all the minions costs 73 normal medals, which have a 100% drop rate as long as you have the watch on (though, fortunately you don't need to be wearing the watch to get the legendary medals, just have the "right" minion out) and don't require you to be using the "right" minion to get them to spawn.
I don't think I'll be going for more than two weapons.
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