Klaus has never been one for delusions or denial; the later is Elijah's cup of tea in all actuality. It's been ingrained in his nature to be cynical, malicious and he tends to follow his nature. If he hadn't, he would never have survived the last thousand years of being hunted down by Mikael.
There's only one person who has the power to sway him from his ingrained (mostly) unremorseful nature. But she hasn't even meet him yet despite how much Klaus yearns to see her because here, in the past, his promise is void for it's hasn't been gifted to her; if Klaus has his way - and he will have his way- that promise will never again be gifted.
So it isn't surprising that he doesn't feel any remorse as his mother and her coffin are desecrated in fire. In fact, he muses it a fitting beginning.
Black smoke fills into the night sky as Wickery bridge and Esther burn.
In the end it takes Maddox.
It's not surprising. Katherine is not suicidal nor stupid. (Unlike her fellow doppelgänger and descendant who not only killed one of his siblings but two.) Of course she wouldn't trust his offer of freedom. After all why would he offer her freedom after five hundred years of being hunted by him? Still, it's suicidal to refuse him and quite rude.
Honestly? Why would he poison wine? Klaus thinks as Katherine once again refuses him (or in this case, a glass of wine) as she glares at him with those deceiving doe eyes that have seduced more than he's killed.
If he wanted to kill her. She would be dead. It's really that simple. Klaus, however, didn't want her death (Death was too easy for those who wronged him after all.) nor for to be her tortured wishing she had simply died in that sacrifice five hundred years ago.
Why doesn't he want to torture her like he once had? Having her stab herself in leg and than switch if she dared got bored whilst he left to go meet his newest doppelgänger.
Once upon a time Klaus had thought Elijah had terrible taste in women. (Though Klaus has learnt what it's like to fall in love helpless and not be able to refuse it or forget it despite the months, years, and decade that's past. Ironically, it could be compared to be sire bond and as the person of his affections, of his last love, would say: karma is a bitch.)
Then there came Elena and Hayley...Katherine was lesser evil and headache. Even as she glares at him, wishing nothing more than his death.
A coy, dark smile spread across the Klaus' lips at the sight. He leans into the soft, black leather of the couch and takes a sip of the wine. Shows the brunette vampire in front of him that she is no threat. He savors the taste of well he aged wine for a moment leaving Katherina to wait. There is no fear quite like the unknown. He thinks he might enjoy Katherine unsure of the future more than he does the wine.
Klaus is an artist and breaking someone is an art as much as sketching and painting are. It might be petty to keep her afraid but Klaus has never said he isn't petty which is more than others.
"Katherina what are you willing to do to be free? Not only be free but to be welcomed into my family as a sister-in-law if Elijah wishes so?"
Making people do want you want is also a form of art; people tend to learn that Klaus is talented in that form of art as well much too late.
He debates on undaggering Kol and Rebekah. In the end his siblings stay daggered.
While he had been on good terms with them in the future he isn't here in the past that is now his present. They will stay daggered until his curse is broken and Mikael is with his beloved wife.
There is a part of him that longs for their company, for his family, but if they were awoken they would purposely cause trouble to get back at him for their time daggered. Too much is a stake at this time.
He hasn't broken his curse, Mikael is somewhere and Klaus doesn't know where despite his vast knowledge of this time, and Klaus has been given a second chance. (If he was less of a pessimistic man, though he preferred the term realistic, he would call this a miracle but he isn't.) He will be damned before he let his siblings make a mess of his second chance.
In exchange Klaus will not harm a hair on the bus boy that Rebekah had been taken with last time, he'll introduce Davina to Kol, and if (great emphasis on the if) he does undagger Finn he'll make sure Sage stays alive so his brother will have something to live for and a reason to not take the hobby of fratricide.
Kol could be annoying and headache inducing (like most younger brothers were) but Klaus would take him over Finn any minute of the day.
He's tempted into ordering Katherine to make Lockwood the werewolf for his sacrifice. In the end he doesn't. Elena's aunt (whatever her name wa- is) was one of the reasons why Caroline held back.
And as appealing as the idea of letting Tyler be the sacrifice Klaus rather not see how Caroline, ever so loyal (to those undeserving of it) Caroline, react to the traitorous mutt being sacrificed.
There's also the prospect of Tyler triggering his werewolf somewhere down the line and Klaus denying him the gift of becoming a hybrid which is much more satisfying idea to toy with.
(As a general rule, Klaus doesn't cast pearls before swine. He will not be giving Tyler the honor of being his first born hybrid or one of his hybrids again.)