In the singleplayer, because you are the blue tribe, you will not see your own tribe's icon - meaning, there are only 3 icons: a red once, from Dakini; a yellow one, from Chumara; and a green one, from Matak tribe. (in multiplayer though you can see the blue icon if one of the other player's tribe is the blue. This icons means nothing more nothing less than which tribes are on this world. In singleplayer level 1, only the Dakini icon is avaliable, so you know you are only facing one tribe. In level 6, both Chumara and Matak's icons are there, so you know there are three tribes in this world (counting with your own). In level 16 there are all the 3 icons - red, yellow and green - so you know that 4 tribes are on this planet and you need to kill them all to win.

Once a tribe is being atacked, that tribe's icon will flash for some seconds. Once a tribe dies, that tribe's icon will flash in a perceptive way, and after ~5 seconds it will disappear.

In multiplayer though, if a tribe's icon is modified (see image 2), it means that you are allied to that tribe - take note that this doesn't mean that tribe is allied with you back!

To ally with a player online, just hold SHIFT and mouse left click on the icon from the tribe's color you wish to ally with. To unally that tribe now, all you have to do is the same thing again.

Online, if all the remaining tribes ally eachother, the game will end and everyone wins.