Yes, go to tavern. Upgrade skills use duplicate warmaiden there. I think the others may be better used as food. But I would definitely use "as books" on warmaiden. 

ClosedPoly said:

I have only been playing for 2 weeks so I dont have much.  Everything has value to me. 

I have 5 extra WarMaiden, 4 SpiritHost, 4 Berserker.  I get them farming but hate to use them for food.  Is there any way I can fuse them to increase all the skills?  Any ideas please.  

You know you can use duplicates as alternative for skill books to level up skills, right? 

Apart from that, the developers promised that some point in the near future, they'll offer something new to do with duplicates. Although we don't know what and it's not entirely clear if it refers only to duplicate legendaries, or also rares and epics. 

Though for campaign farmable rares, I don't worry too much about keeping more than one copy (unless I already know for sure I'll need them for a fusion, as is the case for warmaiden and spirithost). If I'd ever need more for something else, it would be relatively easy to get new ones, which isn't the case for other champions. 

@Trips @L9753

@Trips......Kael is 6-25 now.  Grinding him up to full 60.  I hope that will let me farm 12-3 normal. 

Hello OP

for the farmables it is a great resource of champions's drop to get.

if you want to utilise those champions, such as warmaiden, I would highly suggest using their duplicates as skill books. 

to do that you ought to go to the tavern and they will automatically appear in the skill up area

all the best 

ClosedPoly said:

@Trips......Kael is 6-25 now.  Grinding him up to full 60.  I hope that will let me farm 12-3 normal. 

Save 800 gems for masteries for kael. Trust me. You will be on 12.3 brutal. Take an extended stay on dead lands to finish upgrading warmaiden 

I'll post a screenshot of what I did on my alt account for kael. It may not be perfect but works well for using kael everywhere.

ClosedPoly said:

 But how do I use them.  Which skills?  I bought the first mastery with scrolls.  CR +5 but that puts me on a limited path. 

The good news is that you did not make a mistake with this choice, It sux to mess things up from the very begging, but you are ok for now.

But if you don`t have good idea what you are doing, better take some advise. Later on you will do this by relaying on your own judgment based on your game knowledge, but for now it is good idea to get some advise.