Marty: lacking some social skills?

When I got home from work, I let Marty out of his crate and took the dogs in the back yard.  Kira and Remy ran around like usual.  Marty zipped around and seemed faster than Kira.  Kira ran and got a toy and brought it to me.  When I threw it, Marty chased after Kira and bit at her back legs.  Kira growled and kicked at him but they didn’t fight.  Marty did the same with Remy whenever Remy had the toy.  Then when Remy and I started tugging, Marty started nipping at my legs.  I yelled at him but it didn’t phase him a bit.  I pushed him away but he just ran back and kept nipping at me.  I now call him “strange dog”.

After play time I fed the dogs and then was petting on Kira.  Marty couldn’t stand that Kira was getting attention and started nipping at me and jumping on Kira to try to get attention.  I pet him but it wasn’t enough and he wanted Kira away.  Well, this is one thing that Kira does not tolerate.  No dog is allowed between Kira and me and she snarled and pushed him aside.  Marty backed off and then tried to push in again and I shoved him aside.  He then attacked Remy by pouncing on him and nipping at his tail and legs.  Remy just sat there looking pitiful.