CAMONNA TONG AND FIGHTERS GUILD
The leader of the Fighters Guild, Sjoring Hard-Heart, has made an agreement with Orvas Dren, which has resulted in that Fighters Guild is running a lot of dirty errands for the criminal syndicate. Many of the contracts you get from either the Balmora guildhall or Vivec are very suspicious, and Percius Mercius, the old Grandmaster of the Fighters Guild, will give you counsel on most if you ask him. Hard-Heart is convinced that this pact is necessary if Fighters Guild is to survive on Vvardenfell and he thinks Orvas Dren is "strong, but tough and fair". The competition between Camonna Tong and Thieves guild on one hand and the collaboration between Fighters Guild and Camonna Tong on the other hand may result in a dilemma of taking sides.

_{I trust you %PCName, so I'll tell you that I've made an alliance with the Camonna Tong. These local boys have the wit and the juice. The Thieves Guild hasn't got a chance, but they're bad for business. It's time for change in Vvardenfell, and you can bring about that change. I'd like you to kill the Thieves Guild bosses. Sjoring Hard-Heart}

Below I will go through the suspicious quests one by one.

Eydis Fire-Eye's Orders
Telvanni Agents - In this quest you are sent to Caldera Ebony Mine to take care of "Telvanni Spies" who are also Thieves Guild members. Eydis will stress that these agents are definitely not on a Thieves Guild job and are in fact Telvanni spies having a look at the Caldera Mines. Sure! Whatever you say! That Elmussa Damori, another Thieves Guild member in Caldera, has stolen documents from the Mining Company on another Thieves Guild job, seemingly to investigate Odral Helvi's corruption, has absolutely nothing to do with other thieves spying on the mine. /End sarcasm.

The game dialogue treats this quest as non-suspicious and Mercius will have nothing to say on it, but I still think that this is a Camonna Tong related quest. Maybe it is a result of Odral Helvi whining to his friend Orvas Dren that some thieves are checking out the mine and may get onto them smuggling out ebony.

The Code Book - Here you are asked to retrieve a code book which Thieves Guild members stole from Camonna Tong in order to take over the Skooma trade. This is what Sottilde has to say if you happen to be in both Fighters Guild and Thieves guild (poor you!):

_{Look, %PCRank, I'll tell you what's going on. This code book has dirt on the Camonna Tong and the skooma trade. As soon as we get it figured out, we take it to the authorities and take over the trade ourselves. The Fighters Guild works for the Camonna Tong since Sjoring Hard-Heart took over. You have to decide where your loyalties lie, %PCRank.}

Good online people have decoded the code book, which Sottilde seemed to have some trouble with, and the message within was as follows (the code word was SKOOMA):

_{AIR LOFT (Nevrila Areloth's house, Sadrith Mora)
THIRTYTHREE BOXES
BAG RAT (gro-Bagrat plantation, Ascadian Isles)
THIRTY TWO BOXES DELIVERED
SAT THREE ON (Vadusa Sathryon, Council Club, Balmora)
EIGHT BOXES
FAT LEG (Fatleg's Drop Off, Hla Oad)
TWENTY ONE BOXES DELIVERED
ILL MIR (Might refer to Ilmiril in Ald'ruhn, who possesses a key to the unimplemented Thieves Guild hideout Ald'ruhn Underground)
FOUR BOXES
NAY DEAN (Nadene Rotheran's shack, Gnaar Mok)
EIGHT BOXES
Source: [link]}
So, this code book is a delivery list for skooma. Very delicate information for the Camonna Tong to have lost to the Thieves Guild. Mercius doesn't think that these orders seem strange, but advises you to not kill Sottilde.

Desele's Debt - Here Eydis sends you to collect a "debt" from Desele's House of Earthly Delights in Suran. Only, this debt does not consist of money Desele borrowed from someone and then refused to pay back.
_{I try and run a respectable business and the Camonna Tong keeps asking for this money "for my safety." What is it really for? To keep me safe from Orvas Dren's thugs, that's what it's for, and I'm not paying it. - Helviane Desele}
The debt is to Manos Othreleth on the Dren Plantation, who will make sure Desele goes out of business if she doesn't pay. If you for some reason killed Desele during this quest he will tell you that you don't understand business. "If you kill them, they can't keep giving you money." Mercius tells you that Manos Othreleth works for Orvas Dren, so this may not be a legitimate contract. You should pay the money yourself if she doesn't agree.

Lorbumol gro-Aglakh's Orders
Juicedaw Ring - In this quest you are supposed to get back the Juicedaw Eing from Nar gro-Shagramph, who was supposed to deliver this ring to Ranes Ienith, one of Orvas Dren's top enforcers, but never did. Now he claims that he does not have the ring, but Lorbumol says he is a liar. Camonna Tong business once more.

Silencing Tongue-Toad
Now you are asked to silence an Argonian in The Rat In the Pot who "talks too much". This is a Thieves Guild member and possibly an escaped slave, since he claims to have friends in the Twin Lamps. Quite straightforwardly you are now working as a hitman for Camonna Tong.

Lirielle's Debt
Lirielle Stoine, publican in The Rat In the Pot, owes Suvryn Doves from the Dren Plantation 2000 septims. In fact her brother owed the organization this money, but he was recently murdered in a cave on the Bitter Coast. Sounds suspicious? Yes, it does! Lirielle can't pay this money, but you can find the cave where Ruran Stoine's body is still rotting away with 500 septims on it. That Lirielle has not fetched his body but still knows where it is and that Ruran was murdered is a bit strange  (read "illogical"). Whoever killed him also apparently did not care for getting free money.

Vandacia's Bounty
Lorbumol asks you to kill the Census and Excise agent Adraria Vandacia. This tax agent has, according to Mercius, done nothing to deserve death:
_{Adraria Vandacia is an Imperial tax agent. I don't know why Lorbumol gro-Aglakh would give you a bounty on her. I can only suggest that you disobey orders and do not kill her. If you decide not to kill her, you will likely get no further orders from Lorbumol. He is cruel, petty, and single-minded.}
Seems like another hitman contract for Camonna Tong.

Alleius's Bounty
Now you are asked to kill the magistrate Rufinus Alleius in Ebonheart:
_{One of the magistrates has been giving the Fighters Guild trouble. I don't want the Fighters Guild to have any more trouble from Rufinus Alleius.}
I'm pretty sure that the trouble Fighters Guild is experiencing is caused from their collaboration with Camonna Tong, and Orvas Dren is the one who actually has trouble with the magistrate. Either way, of course they are going to get in trouble with the law if they notoriously break it. Mercius warns you that killing an Imperial Magistrate is a serious offense and that you should refuse this order.

Sjoring Hard-Heart's Orders
Remove the Heads of the Thieves Guild - Now you are asked to kill the Thieves Guild Captains Big Helende, Sugar-Lips Habasi and Aengoth the Jeweler. This is exactly what Camonna Tong wants, considering the war going on between these two guilds.

Kill the Master Thief - Now you are to kill Gentleman Jim Stacey. Hard-Heart claims that once you have done this, he will make you the new Guildmaster and retire. If you do this and return, however, he turns on you:
_{I hear you killed the Master Thief. Great work, %PCName. Thanks for taking care of the Thieves Guild for me. Now the only one who can threaten my position...is you. You showed promise, but a bit too much ambition. You will not be missed.}

If you are the master thief, this is what happens:
<sub>What? You're the Master Thief? Well, why didn't you say so from the start? Tell you what, %PCName, between you and me and Camonna Tong, we've got a good deal here. Let's start by you telling me everything you know about the Thieves Guild operations in Vvardenfell.

That information will help a great deal when I take over the Thieves Guild and the Camonna Tong myself. Now who's the "Master Thief," %PCName?</sub>

So, it turns out Sjoring thinks that he is tricking Orvas Dren and he aims to take over Camonna Tong as well as Thieves Guild, turning himself into the new Kingpin with complete authority over the crime and smuggling operations on both sides. He sure is ambitious!