I've been playing Regulus since September 08, and I'm seeing a bunch of threads about him, so I thought I'd toss up a guide on how I play him. Next time I play (might be a while, since Dragon Age is like crack) I'll see if I can't put together a decent replay or two.
Assume Cataract 3v3 unless noted otherwise.
Skills:
Snipe
Scope
Mines
Snipe II
Mark
Tracking
Mines II
Mines III
Save
Mark II + Mines IV
Items and Upgrades:
Favor - Renewal
Alternative Favor Items: Until you are comfortable with this Regulus' role it's fine to go Swift Anklet - the speed keeps you out of trouble.
Heaven's Wrath - most people use this like a hammer, but it's actually a scalpel.
You raise the enemy "flee" threshold tremendously once your opponents see you use HW to get a Snipe kill through fog of war enough times. If you are using it just for grunt kills then you are wasting it, imo
Scaled Helm
Two Combat Mana Pots
Observation Ward
Unbreakable Boots
Currency I
Vlemish Helm
Plenor Helm
Wand of Speed
Priests and Angels or Catapults
Giants
My reg is built in two stages.
Stage I:
1. A complete Snipe Blitz. Renewal + Scaled Helm + mana pots allows you to snipe from the field through level 4-5 without return to base, and Snipe I and II cost relatively little mana for their range. If your team is any good it means you control all the flags and develop a respectable rank advantage (if your team is no good then you made a serious error playing Regulus). If your opponents make any mistakes it means you are getting kills, early. Even without mistakes they are behind their towers or hitting home for most of the early game. To reiterate - spam the hell out of snipe, all the time. We'll talk about Snipe Tactics and Priorities further down.
2. Levelling - you are the mid guy, both because it sets you up for the snipes and because you are fast enough to cap mid and make it back to your lane tower in time for grunt xp. The combination should put you on par or higher level than most of the other players, and if you are getting last hits on the Snipe then you'll quickly outstrip everyone else. That's important, because this Reg peaks early.
3. Towers - any time you are left alone in a lane you are putting pressure on enemy towers. Your auto-attack damage is pathetic, but you can hit from outside tower range, so your opponents have to send someone over eventually unless they want to lose a tower early
4. You are and will be throughout play the weakest, squishiest DG on the field. Your map awareness and positioning need to be flawless to make this build work, or you will be ganked repeatedly. At this stage you are never, ever going to be within melee range of an opponent. You will never be within Swap range of DA. You will never exchange shots with a competent TB, and you stay far away from Erebus. If you are just starting out with this build you might want to go with Swift Anklet rather than Renewal so you have more time to respond.
5. You are buying currency I, either because you are getting the kills or because you need less gold than anyone else on your team. Basically once you have unlimited mana you are set, and you can get that with less than 5k gold.
Stage II:
1. You have at least two points in Mines and one point in Mark, you have Tracking Bug, you have a huge mana pool and great mana regen. Grab some ports and go hunting. You are in the business of interrupting any tidy 1v1 situations you see develop with a Snipe/Port/Mark/Mines/Pew Pew/Mines/Snipe, and business is good.
2. When you aren't aiding your more robust pals you are mining the daylights out of enemy towers or setting up mines as a protective barrier against DGs while you whittle them down with pew pew. If no other targets present themselves you can snipe towers across the map while doing this.
3. You are spamming Mark like it's going out of style. Every enemy DG should be carrying a mark, all the time, and as soon as they use an ability you should be replacing it on them. The ability has ridiculous range, so you don't have to engage the bad guys to use it.
4. You are using your abilities as an equalizer. You can't match the autoattack damage of your opponents and you are so much squishier than them. You have to be sneaky, a guerilla in the mist. Stack your 6 mines and have three more waiting, never engage on equal terms, and jump in on every hurting enemy. Use your bugs to make sure enemies go all the way back to base to heal up, rather than just behind a tower. The thing to remember about Reg is that his best abilities don't require him to be anywhere near the target. Embrace that.
5. Once you are cheaply geared you can spend money on grunts. Once you have catas you can start making portal runs. Reg isn't like Oak or LE - he can't run through the portal towers and expect to get out again against a good team, so it's probably best to get some cheap speed items, knock the towers down first, and get the Gold/Celerity flag to neutral or better before you start. Once you do that, though, mining the approach and locking portals is what you will be doing through endgame.
OK so that's what it looks like, Sniping early and often, and building up Mines and Mark to bring the pain. Now let's talk about map control.
Map Control and Reg:
I was talking to Orcun and Posidenii (best Reg/Rook combos in the biz, back in the day) a few months back about the merits and flaws of Reg. I was saying he had no map control, that he would always get pushed off of a flag by any other DG, and would always be second-tier as a result. They made a very simple counterpoint.
*Map control isn't Reg's job. It's his allies'.*
If your reg is trying to push LE off of the fortitude flag then your reg will be hurting, and so will your team. But if your allied UB is trying to push LE off the flag and you are throwing in a couple of snipes from mid then LE will have to retreat or die.
Your job as Reg is to give your allies leverage and help them net kills or towers. That's it. So let's look at the primary tool you will be using to make that happen.
Sniping Priority and Usage:
You want your snipes to mean something, because they cost you mana. Here's the priority of targets I use:
DGs:
Reg (especially once you have Tracking Bug)
TB
DA
Rook
UB
Oak
QoT
LE
Sedna
*Notice how all the assassins are on top? Yah, that's because they don't have monks unless their allies are giving them some. Any time you can target the monks first you should, assassins depend on them to stay in the field early.
Tactical Priorities:
Critically wounded opponent
Opponent committing to battle with ally
Enemy Reg
Non-Sedna opponent without monks
Opponent uncommitted to battle
Enemy outer towers
Enemy portal towers
Enemy center lane towers
When you roll Reg chances are someone on the other side will too, because he's fun to play. The enemy Reg will always be a priority target, because he is squishy, but also because if you leave him alone he will negate you. A good enemy Snipe Reg is about the only thing that will force you to buy breastplates, because he will be trying to suppress you exactly the same way you are trying to suppress him. You gotta keep that guy pinned down, and that's why you got Tracking Bug, right?
Peaking Early - Snipe will be effective through enemy level 7 or so, and Mines and Mark will hold their utility through enemy level 12. After that you are going to have more trouble being effective. If you make it to enemy level 15 and the enemy citadel isn't ankledeep in siege then you have a serious problem and will lose.
If things go according to plan, however, your early and constant sniping has given your team the edge it needs to end the game while you are still strong. You have a rank and tower advantage, use it to buy your siege grunts as soon as possible. Apply pressure to mid until they are a presence, and then lockdown enemy portals. You aren't going to win late 3v3 battles at the center of the map against a good LE/Rook/UB team, so don't try.
Conclusion: In the right hands and with the right team this Regulus can take on any opponent set of DGs or players. You really need to push your map and situation awareness beyond what any other DG requires to make it work, however. I've had a lot of fun with this build, so let me know if you have any questions or comments, and I'll see if I can't rustle up a replay or two