I'm going to assume that the slope is at the back of your entire lot that we are looking at . . seems that some of it may be needed to hold up the fence of your neighbor behind . . you can make a 2 to 1 slope to their fence (for every 1' of height to bottom of their fence wall, you come into your space 2' so you are making a triangle with the eroding mound that was left to you that is more even all the way across . . instead of removing the dirt, spread the rest of the dirt across the rest of your lot to level before you build. You could slope it more gently than that but you have a large space to lose the extra dirt into.

You can plant the slope with groundcover to hold the soil in place .. then the dogs will be able to use it . . if this is the rear of your yard, I recommend you plant some tall columnar shrubs or trees (yew tree is good for this in Mediterranean climates) to hide the neighbors fence with green in a row along the property line . . paint the block fence on your side with whitewash and send water and power out to your garden area so later you can use a fountain outdoors.

Hey thanks a "lot"! :P Honestly I didn't though about what elainesteinke said, about making these decisions before making the house, what a good point! And yes, the slope is the back of the lot, it would be in the end of the backyard.

A waterfall!

Yep, easy to make a gentle slope and spread the dirt around before you build . . not expensive and now fully useable.

Need some sort of terrace and soil anchoring plants to stop the heavy wall at the top from slipping and to hide that and the other ugly wall