Hey Tarl, here's the strategy I use with regulus. I play single player mostly(I get a very high Lag on multiplayer), it works with hard and nightmare AI even if youre outnumbered against the opposing team.
Most people prefer to start out with scalem helm and banded armor I dont, your choice, I instead spend 500 on the first tower health upgrade, get a teleporter amulet or scroll and teleport to the furthest tower next to the fortress on the right or left side(I play on zikurat map mostly). If you time this move right you'll be able to capture two flags and be at level 2 before the first wave of creeps or other demigod show up.
Regulus has very liimited amount of health and mana at this stage, mine upgrade are useless. I go with snipe and range upgrade, the range upgrade is very important, you can start attacking towers right away without getting hit.
Now the trick here is to stay put at one of the tower in the center, out of the range of the opposing tower. the creep waves would clash with each other right in front of you. The most important thing is to stay steady, DONT INDIVIDUALLY ATTACK ANYONE, let Regulus auto-attack otherwise he'll lock onto a demigod and chase him behind the enemy tower resulting in death. Fall back to the other tower if the tower you're defending gets taken down. If you wanna level up faster you can use the angelic fury on level 3 to get splash damage but mana would severly limit your use. I would suggest waiting to get a snipe kills on the other end of the map, regulus snipe damage is pretty decent at the start and the mid point of the game. you should get the second point at level 4 if you decide to rely on snipe else go with mine upgrades but dont use them til the 2-3 mine upgrade. If you are forced to return to the health stone up to this point by any chance concentrate on buying the two helm that will fix regulus mana problem, you need the vlemish faceguard(1750) and plenor battlecrown (1500) to put your mana per second rate at around 30+. needless to say keep picking up any health left by dead demigods or if you have sedna on your team you can stand next to her to get an increased health rate, one of the priest from another demigod might heal you too, just stand in their way.
Now focus on maximising your mines, thats the strongest attack Regulus has. Shrapnel mines and the mark of betrayer are the only two things you'll need to win. Also get a narmoth's ring as soon as you can, its really helpful. Just try and stay at a distance from melee based demigods (UB, Oak etc.) and only attack the oppsing creep force from behind yours. One thing that you should focus on from here is maximising your attack speed, try getting above 60%(machinegun upgrade) add that with Ashkandor (18000) and it becomes a lethal combo. If it helps, Queen of thorns is the weakest Demigod even with Nightmare AI, you can attack her head-on most of the times.
Thats the beginning and mid-game strategy I use for Regulus, you can take out entire creep waves with a well placed mine attack, take off demigods trying to retreat and pretty much dominate. I have used this strategy against 5 hard and nightmare AI (3 hard and 2 nightmare)and still be able to get upto 50 kills in one game with 1 or 0 death, you can even stop upgrading your abilities after level 10-12 (after shrapnel mines and two mark of betrayers) and still dominate with this strategy. As a test you should always be atleast a level or two above any other enemy demigods, It should'nt be a problem if you follow the strategy. I usually end up with 100+ per second mana and health rates with 4x critical strike, enough to take on demigods next to their health stone.
Hope this helps, feel free to ask if you get stuck at any point.
