In halo wars I use odsts to combat lots of tactics, mainly the scarab tactic, I have all infantry upgraded, spawn three Spartans and move them to the enemy bases once they are there I drop the men in and spam it, each time one dies, 5 replace it, it should take about 5 minutes for normal bases 10-20 if defended with units, the only downside is money and tech, without either it is useless and the only counter is snipers or flame units or if I am rushed early, people consider this man spam, it is but it's devastating and I've never been countered by anyone except rush which I don't count as a counter more of a f**k you and your tactics, in 7-8 minutes I could have ODSTs or if I upgraded spartans 10 minutes, feel free to comment of some bad sides or good, no hate comments and please comment your own infantry tactics, remember its a base killer and scarab killer tactic, if you use it right