Thanks a lot for your great comment. You are totally right that the situation is different when you rely on renting cards. But still it's important to develop monsters only as much as necessary in respect to the summoner that you are going to rent. It can also be a good idea for example to develop several cards of the same type. For example with reward cards. You make two level 2 cards. You rent one out and you use the other one. Once you develop your deck, you can cancel the rent and merge all the cards together.

Also there seems to be some issues with the audio, your voice goes down for several seconds a few times (like 6.26, 7.07).

I'll need to check my settings. Thanks.