No, never had any fusions.
Since there was an update, their abilities have gotten better (golden variety abilities that affect all the enemy / ally cards, instead of just one.) They are supposed to be over powered cards that dont waste a second turn to gain good abilities. That said, they are weak in attack and health stats.
Because they cant get a boost in stats from fusion, you have to evolve them to give them a fighting chance. You can only really evolve them once (sacrifices a duplicate) before needing to grind higher levels of adventure, which the AI is really unfairly overpowered.
The only one i recommend is to use is Lisa right now, since she has Bdsm and 15 attack 22 health as of level 10. She is from the 3rd Adventure set, which isnt impossible to beat.